TY - CONF A1 - Bonse, Jörn T1 - A survey of surface functionalization through laser-induced periodic surface structures N2 - Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon that can be observed on almost any material after the irradiation by linearly polarized laser beams, particularly when using ultrashort laser pulses with durations in the femtosecond to picosecond range. During the past few years significantly increasing research activities have been reported in the field of LIPSS, since their generation in a single-step process provides a simple way of nanostructuring and surface functionalization towards the control of optical, mechanical, biological, or chemical surface properties. In this contribution the mechanisms of formation and current applications of LIPSS are reviewed, including the colorization of technical surfaces, the control of surface wetting properties, the mimicry of the natural texture of animal integuments, the tailoring of surface colonization by bacterial biofilms, the advancement of medical pacemakers, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - Seminar, ALPhANOV - Centre Technologique Optique et Lasers CY - Talence, France DA - 07.06.2019 KW - Laser-induced periodic surface structures, LIPSS KW - Surface functionalization KW - Applications KW - Femtosecond laser PY - 2019 AN - OPUS4-48199 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jansson, P. T1 - EURAD: SFC WP Spent fuel characterisation and evolution until disposal N2 - The European Joint Programme on Radioactive Waste Management (EURAD) has been launched to coordinate activities on agreed priorities of common interest between European partners. The main actions include scientific and technical activities on radioactive waste characterization and processing, interim storage of radioactive waste as well as predisposal and disposal solutions. As part of the programme, the work package on Spent Fuel Characterization and Evolution until Disposal (SFC) was proposed and accepted by the European Commission. The objectives of this work package include the development of beyond-state-of-the-art characterization techniques for spent nuclear fuel during its evolution from reactor unloading until disposal, the understanding of the spent fuel performance during prolonged storage, transport and emplacement in a deep geological repository, the understanding of the behaviour of fuel, cladding, pellet-cladding interaction and ageing effect under normal and postulated accident scenarios until disposal, and contributions to operational safety concepts for fuel handling at spent nuclear fuel packaging facilities. T2 - EURADWASTE '19 CY - Pitesti, Romania DA - 04.06.2019 KW - Radioactive waste KW - Interim storage KW - Transport KW - Disposal KW - Spent fuel characterisation PY - 2019 AN - OPUS4-48211 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten T1 - Quick Seasonal Performance Testing for Heat Pumps N2 - To determine the seasonal performance of heat pumps for energy labelling this study proposes a two-point-method that could conceivably be an alternative to the European standard EN 14825 and similar test standards such as ISO 13256. Heat pumps were tested in line with the EN 14825. The reduction of measurement points, from between five to seven (EN 14825) to only two (two-point-method), leads to 60 % savings in cost and time. It is shown that the shortened method can be used to determine the seasonal energy efficiency of heat pumps with the same degree of precision compared to EN 14825. T2 - ECEEE Summer Study 2019 CY - Hyerès, France DA - 03.06.2019 KW - Heat pump KW - Energy label KW - Testing KW - Coefficient of performance KW - Screening PY - 2019 AN - OPUS4-48274 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten A1 - Simo, Anne T1 - Quick Seasonal Performance Testing for Heat Pumps N2 - To determine the seasonal performance of heat pumps for energy labelling this study proposes a two-point-method that could conceivably be an alternative to the European standard EN 14825 and similar test standards such as ISO 13256. Heat pumps were tested in line with the EN 14825. The reduction of measurement points, from between five to seven (EN 14825) to only two (two-point-method), leads to 60 % savings in cost and time. It is shown that the shortened method can be used to determine the seasonal energy efficiency of heat pumps with the same degree of precision compared to EN 14825. T2 - ECEEE Summer Study 2019 CY - Hyerès, France DA - 03.06.2019 KW - Heat pump KW - Energy label KW - Testing KW - Coefficient of performance KW - Screening PY - 2019 SP - 1547 EP - 1552 AN - OPUS4-48275 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Laser-induced periodic surface nanostructures N2 - This presentation reviews the current state in the field of Laser-induced Periodic Surface Structures (LIPSS). These surface nanostructures are a universal phenomenon and can be generated on almost any material by irradiation with intense linearly polarized radiation. LIPSS are formed in a “self-ordered” way and are often accompanying material processing applications. They can be produced in a single-step process and enable surface functionalization through the adaption of optical, mechanical and chemical surface properties. Their structural sizes typically range from several micrometers down to less than 100 nanometers and show a clear correlation with the polarization direction of the laser radiation. Various types of surface structures are classified, relevant control parameters are identified, and their material specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics, through time-resolved optical experiments and theoretical simulations. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. T2 - International Symposium “Fundamentals of Laser Assisted Micro- and Nanotechnologies” (FLAMN-19) CY - St. Petersburg, Russia DA - 30.06.2019 KW - Laser-induced periodic surface structures, LIPSS KW - Femtosecond laser KW - Surface functionalization KW - Ultrafast scattering PY - 2019 AN - OPUS4-48420 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tiebe, Carlo A1 - Majewski, J. T1 - Ansprechzeiten von Wasserstoff-Sensoren N2 - Die Effizienz von Gassensoren zur sicheren Verwendung von Wasserstoff hängt wesentlich von der Reaktion des Sensors auf eine Änderung der Wasserstoffkonzentration ab. Daher wurde die Ansprechzeit von fünf im Handel erhältlichen Wasserstoffsensoren unterschiedlichen Messprinzips bestimmt. Experimente haben gezeigt, dass alle Sensoren die Anforderungen der Norm ISO 26142 übertreffen; es wurden Ansprechzeiten im Bereich (t90-Zeiten) von 2 s bis 16 s ermittelt. Die Ergebnisse können mit Exponential- oder Sigmoidalfunktionen approximiert werden. Es kann gezeigt werden, dass die Ergebnisse zum transienten Verhalten sowohl von den Betriebsparametern der Sensoren und Prüfverfahren als auch von den experimentellen Bedingungen wie Gaswechselrate sowie Konzentrationssprung abhängen. T2 - 7. HYPOS-Dialog - Innovative Wasserstoffsensorik CY - Halle (Saale), Germany DA - 19.06.2019 KW - Wasserstoffsensor KW - Ansprechzeit KW - t90-Zeit KW - Prüfverfahren PY - 2019 AN - OPUS4-48397 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rütter, H. T1 - Combining CO2 streams from different emitters ‐ a challenge for pipeline transportation N2 - Depending on the CO2 generating and the capture process as well as on consecutive purification steps applied, CO2 streams from different emitters may differ in their composition. When CO2 streams with different compositions are fed into a larger pipeline network, there are several aspects that must be considered: i) chemical reactions, such as acid formation, may occur within the joint CO2 stream; ii) there may be a variation of mass flow rate and CO2 stream composition within the pipeline network if the feed-in behavior of different CO2 sources changes with time. Potential impacts of changing CO2 stream compositions and mass flow rates in CCS cluster systems were investigated in the collaborative project "CLUSTER" (see also www.bgr.bund.de/CLUSTER). In this presentation, we focus on the experimental investigations of formation and condensation of strong acids and their impacts on the corrosion of pipeline steels. When SO2, NO2, O2 and H2O are present simultaneously in CO2 streams chemical cross-reactions may occur leading to the formation of strong acids such as sulfuric and nitric acid. To prevent this acid formation the concentration of at least one of these four impurities must be kept very low (e.g., Rütters et al., 2016). At temperatures below the acid dew point temperature, acids will condense, e.g., on pipeline steel surfaces. In turn, these acid condensates may trigger steel corrosion. To better understand the process of acid formation and condensation and its implications for steel corrosion, exposure tests were performed on pipeline steel X70 in dense CO2 with varying SO2, NO2 and O2 concentration under high pressure and at 278 K in an observable autoclave, in which water was added as droplets or as vapor. Further, electrochemical tests were carried out with X70 specimens immersed in 500 mL CO2-saturated synthetic condensate solution or in droplets of the same solution on the specimen’s surface. Depending on impurity concentrations in the CO2 streams, condensates consisting of different relative amounts of nitric and sulfuric acid were formed. In condensates containing both nitric and sulfuric acid, corrosion rates were higher than the sum of those of the individual acids. In addition, corrosion products and forms depended on the condensate composition. Investigations of water droplets on steel surfaces in impurity-containing dense-phase CO2 revealed the diffusion of SO2 and NO2, followed by cross-reactions forming corresponding acids. An increase in droplet size (from 1 to 5 µl) lead to higher corrosion rates. However, in comparison to measurements in bulk solution, corrosion reactions in droplets resulted in thick, high-resistance corrosion products and observed droplet corrosion rates were significantly lower. In addition, the possibility of acid droplet formation and growth in impure liquid CO2 is influenced by the wetting behavior of the acid droplet on the steel surface. Thus, the contact angle between a water droplet and the surface steel specimens in a CO2 atmosphere was investigated in a high pressure view cell following the sessile drop method. The contact angle wasand found to be larger at higher CO2 pressures (studied from 5 to 20 MPa) and at higher temperatures (e.g. 278 K to 333 K). Further, measured contact angles were larger on rough than on smooth metal surfaces. In addition, acid formation reduced the contact angle, i.e. lead to better wetting, thereby stimulating condensation that was followed by a corrosion process. These detailed insights on the complex interplay of acid formation, condensation, wetting behavior and corrosion allow a better assessment of material suitability for pipeline transportation of impure CO2 streams T2 - TCCS-10 The 10th Trondheim Conference on Carbon Capture, Transport and Storage CY - Trondheim, Norway DA - 17.06.2019 KW - arbon capture KW - utilization, and storage (CCUS) technology KW - corrosion KW - condensate KW - electrochemical characterization KW - pitting corrosion KW - impurities KW - carbon steel PY - 2019 UR - https://www.sintef.no/globalassets/project/tccs-10/dokumenter/tccs10---book-of-abstracts.pdf AN - OPUS4-48369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nagelschmidt, Sven A1 - Herbrich, Uwe A1 - Qiao, Linan T1 - Applicability of developed calculation models to predict long-term behavior of metal seals – Necessary scope of tests N2 - The long-term sealing behavior of metal seals, assembled in the lid system of casks for transportation and storage of radioactive materials, has been investigated. For that purpose, phenomenological models describing the time- and temperature dependent behavior have been introduced by BAM since 2016, e.g. by using the time-temperature superposition principle. Results have shown that these models describe the relaxation behavior adequately and are suitable for extrapolations. In this work, the applicability of these models is checked by analyzing the necessary scope of tests, which must be carried out to get sufficient information about the long-term behavior of metal seals based on short-term tests. T2 - Waste Management Conference CY - Phoenix, Arizona, USA DA - 03.03.2019 KW - Metal seal KW - Time-temperature superposition principle KW - Transportation and storage cask KW - Long-term interim storage PY - 2019 SP - 19311, 1 EP - 6 AN - OPUS4-48353 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Akkerman, Floris T1 - One step back, two steps forward - resource efficiency requirements within ecodesign N2 - Resource efficiency is a much discussed topic in terms of improving the sustainability of energy related and energy non-related products. Resource efficiency aspects such as the availability of spare parts, the ability to dismantle, etc. have been included in draft working documents in the revision of several already existing Ecodesign regulations as a first step. However, often these aspects are not consistent with the current technology and design of these products. A possible reason could be a lack of sufficient consultation or of a methodology which is sufficiently tailored for this topic. The established strategies and tools, used by policymakers, such as the Methodology for the Ecodesign of Energy-related Products (MEErP), do not seem to deal with these aspects appropriately. Draft requirements need to be very well developed before being discussed with member states and other related stakeholders, because including resource efficiency parameters could lead to additional, very wide-ranging effects on society. This topic cannot be covered well with legislative tools developed primarily for energy aspects. In this paper, a method is presented which can be used to combine products’ properties with crucial resource efficiency indicators. The method can be used to develop a set of draft legislative requirements and to pre-evaluate these requirements by target groups which would be affected by additional legal requirements. These include: market surveillance authorities, standardization organizations, manufacturers and their associations, environmental organizations and research facilities. The method incorporates stakeholders’ feedback to identify potential resource efficiency measures for materials and/or products, their impact on the European ecology, economy and society. Based on this it would help to develop legislative requirements which are feasible and desirable. The results can then be fed into the formal legislative process, probably speeding it up. T2 - ECEEE 2019 Summer Study on Energy Efficiency CY - Belambra Presqu'île de Giens, France DA - 03.06.2019 KW - Circular economy KW - Ecodesign KW - Energy policy KW - Resources PY - 2019 AN - OPUS4-48427 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Vibrational density of states and molecular mobility in a polymer with intrinsic microporosity PIM-1 as revealed by inelastic neutron scattering N2 - Polymers with intrinsic microporosity are promising candidates for the active separation layer in gas separation membranes. Here, by means of inelastic neutron scattering, the vibrational density of states (VDOS) and the molecular mobility were investigated for PIM-1, the prototypical polymer with intrinsic microporosity. The results are compared to data measured for a more conventional high-performance polyimide used in gas separation membranes (Matrimid). The measured data show the characteristic low frequency excess contribution to the VDOS above the Debye sound wave level, generally known as the Boson peak in glass-forming materials. In comparison to the Boson peak of Matrimid, that of PIM-1 is shifted to lower frequencies. This shift is discussed considering the microporous, sponge-like structure of PIM-1 as providing a higher compressibility at the molecular scale than for conventional polymers. Elastic fixed window scans were measured on a neutron backscattering spectrometer to have an overview about the molecular dynamics at a time scale of ca. 1 ns. The temperature dependence of the estimated mean squared displacement shows a step-like increase in the temperature range from 100 K to 250 K indicating the onset of some molecular mobility. The nature of this motional process was analyzed in detail by quasielastic neutron scattering combining Time-of-Flight and backscattering where the data are discussed with regard to both the q- and the temperature dependence. T2 - 7. European Conference on Neutron Scattering 2019 CY - Saint Petersburg, Russia DA - 30.06.2019 KW - Neutron Scattering KW - Polymer of intrinsic microporosity PY - 2019 AN - OPUS4-48421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Niederleithinger, Ernst A1 - Niederleithinger, Ernst A1 - Katzenbach, R. A1 - Hillmann, S. A1 - Schallert, M. A1 - Unseld, H. A1 - Willmes, M. ED - Bullock, P. ED - Verbeek, G. ED - Paikowsky, S. ED - Tara, D. T1 - A Framework for Nondestructive Testing Used in Foundation Reuse Projects N2 - The reuse of existing foundations is considered in various construction Projects to save time and costs while avoiding unnecessary interference with other underground objects. Because the design and as-built drawings might not be complete and questions may arise regarding the condition of the foundations, a detailed investigation is a prerequisite for the planning process in most cases. Nondestructive testing (NDT) techniques are a core part of this endeavor. The processes and procedure for foundation reuse planning are not yet standardized, and the possibilities and limitations of NDT methods are not known to many planners and stakeholders. The German research Project REFUND (2014–2016) has developed charts for the planning and Investigation process that consider available standards and the current state of the art in NDT. These charts are separately available for single and strip, slab, and pile foundations. Available NDT methods have been compiled and evaluated for specific tasks at these foundation types, including their respective limitations. The procedures have been successfully tested in two real-world projects. The results from these projects enable planners to improve the reliability of the process while potentially saving significant resources. This paper discusses the procedures for pile foundations and demonstrates the use of various NDT methods in a project on the reuse of electrical tower foundations. KW - Foundation reuse KW - Pile integrity testing KW - Parallel seismic PY - 2019 SN - 978-0-8031-7667-6 DO - https://doi.org/10.1520/STP161120170159 VL - 1611 SP - 238 EP - 253 PB - ASTM International CY - West Conshohoken, PA, USA AN - OPUS4-48795 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weise, Frank T1 - AKR an Betonfahrbahndecken – ausgewählte Einflussgrößen und neuartige AKR-Vermeidungsstrategie N2 - In den letzten Jahren sind im deutschen Bundesautobahnnetz vermehrt Schäden an vor 2005 hergestellten Betonfahrbahndecken aufgetreten, die mit einer Alkali-Kieselsäure-Reaktion (AKR) in Verbindung gebracht werden. Vor diesem Hintergrund werden in diesem Beitrag zunächst die Voraussetzungen und ausgewählte Einflussgrößen für eine schädigende AKR aufgezeigt. Besondere Aufmerksamkeit wird dabei der Rolle des Tausalzeintrags durch den Winterdienst bei Betonfahrbahndecken geschenkt. So wird mit Löseversuchen in 1 M KOH-Lösung zweier Gesteinskörnungen bei 80 °C gezeigt, dass mit zunehmender NaCl-Zugabe die Löslichkeit von SiO2 zunimmt und die von Al2O3 eine Verminderung erfährt. Basierend auf dem so exemplarisch erbrachten Nachweis für die Verstärkung der schädigenden AKR durch das Tausalz wird die Notwendigkeit und Richtigkeit der Durchführung von AKR-Betonversuchen mit Alkalizufuhr im ARS 04/2013 zur zukünftigen Vermeidung von AKR-Schäden an Betonfahrbahndecken im Rahmen von Neubau- und Erneuerungsmaßnahmen im Bundesfernstraßennetz belegt. Zusätzlich durchgeführte WS-Grundprüfungen nach dem ARS 04/2013 mit den beiden Gesteinskörnungen der Löseversuche veranschaulichen, dass die nach der Alkali-Richtlinie des DAfStb als unbedenklich eingestuften Gesteinskörnungen bei den Betonversuchen mit Alkalizufuhr durchaus als alkaliempfindlich bewertet werden können. Dies wiederum führt zu einer Verminderung der für den Betonstraßenbau verfügba-ren Gesteinskörnungen. Vor diesem Hintergrund wird nach neuartigen AKR-Vermeidungsstrategien gesucht, die auch eine Verwendung der als grenzwertig alkaliemp-findlich eingestuften Gesteinskörnungen erlaubt. Einen möglichen Lösungsansatz stellt in diesem Kontext die Innenhydrophobierung des Fahrbahndeckenbetons dar. Es soll so durch die Behinderung des Feuchte- und Tausalzeintrags in den Beton der AKR-Schädigungsprozess signifikant vermindert werden. Für die Bewertung der Leistungsfähigkeit der Innenhydrophobierung zur Vermeidung bzw. Verminderung einer schädigenden AKR in Betonfahrbahndecken wird zurzeit im Auftrage der BASt an der BAM ein Forschungsvorha-ben bearbeitet. Im Rahmen dieses Beitrags werden erste Ergebnisse dieses Projekts vorge-stellt. So wird exemplarisch an einem Oberbeton (D > 8)/Unterbeton und einem Oberbeton 0/8 mit einer alkaliempfindlichen Gesteinskörnung der Einfluss zweier Hydrophobierungsmit-tel auf die Frisch- und Festbetoneigenschaften ganzheitlich aufgezeigt und bewertet. Bei Letz-teren stehen zunächst die mechanischen und hygrischen Parameter sowie der Frost-Tausalzwiderstand im Vordergrund. In einem weiteren Schritt wird der Einfluss beider Hydro-phobierungsmittel auf die schädigende AKR mittels AKR-Betonversuchen mit Alkalizufuhr beleuchtet. Dabei gelangen ergänzend zur Beurteilung des Tausalzeintrags die Laser-Induced Breakdown Spectroscopy (LIBS) und zur Bewertung der Ausprägung der AKR und sekundä-ren Ettringitbildung (SEB) die Dünnschliffmikroskopie zum Einsatz. T2 - 9. Betonfachtagung CY - Berlin, Germany DA - 12.11.2019 KW - AKR, Betonfahrbahndecke, Tausalzeintrag, Innenhydrophobierung PY - 2019 SN - 978-3-7640-0633-4 SP - 159 EP - 175 PB - Verlag Bau + Technik GmbH CY - Erkrath AN - OPUS4-51563 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Munzke, Dorit T1 - Monitoring of type IV composite pressure vessels with multilayer fully intregrated optical fibre based distributed strain sensing N2 - We present the results of distributed fibre optic strain sensing for condition monitoring of a hybrid type IV composite fully wrapped pressure vessel using multilayer integrated optical fibres. During load cycle tests material fatigue could be localised and monitored 17,000 load cycles before burst. Results have been validated by acoustic emission analysis. T2 - 12th International Conference on Composite Science and Technology CY - Sorrento, Italy DA - 08.05.2019 KW - Hybrid composite pressure vessel KW - Distributed fibre optic sensing KW - Acoustic emission analysis KW - Structural health monitoring PY - 2019 AN - OPUS4-47995 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Revealing effects of chain scission during ageing of EPDM rubber using relaxation and recovery experiment N2 - Both chain scission and crosslinking reactions occur during ageing of EPDM rubber. However, with many conventional polymer analysis methods such as hardness and DMA, it is hardly possible to obtain information about the contribution of each reaction type to the measured data. For example, hardness and Tg both increase during ageing of EPDM, indicating crosslinking during ageing, but it is not clear whether this is partly counterbalanced by chain scission reactions which would lower hardness and Tg. An indication that chain scission reactions probably counteract the hardness or Tg increase by crosslinking is given by Compression Set (CS) measurements. CS exhibits a higher change than hardness or Tg, as CS increases additively through both chain scission and crosslinking reactions. In order to elucidate the share of chain scission reactions in the total degradation, a method testing relaxation and recovery behaviour using DMA equipment was applied. The method revealed the strong influence of chain scissions, leading to more pronounced relaxation and higher residual strain after compression. KW - Compression set KW - DMA KW - Nnetwork KW - Crosslinking PY - 2016 DO - https://doi.org/10.1016/j.polymertesting.2016.10.026 SN - 0142-9418 SN - 1873-2348 IS - 56 SP - 261 EP - 268 PB - Elsevier Ltd. AN - OPUS4-38012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja T1 - Lifetime Prediction of Elastomeric O-Ring Seals N2 - BAM is the federal institute for materials research and testing in Germany. One of our tasks is to evaluate the safety of casks designed for transport and/or storage of radioactive waste. As elastomeric seals are used in the containers as safety-relevant parts, it is our goal to be able to evaluate the service lifetime of the seals with regard to the requirements for long-term safety (40 years and more) of the containers. For this reason, an accelerated ageing programme with selected rubbers often used for seals (HNBR, EPDM and FKM) was started. Ageing was performed at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) for up to 2 years. For assessing properties related to the sealability, O-rings were aged in compression by 25 % (corresponding to the compression during service) between plates. For comparison, uncompressed O-rings were aged as well. The aged materials were characterized with conventional polymer analysis methods such as hardness and tensile tests, but also with more seal-specific methods such as compression stress relaxation (CSR, reflecting the loss of sealing force of a compressed seal over time), and compression set (CS, representing the recovery behaviour of a seal after release from compression). CS is chosen as the property for lifetime prediction as it is both sensitive to degradation and related to the seal performance. CS data is extrapolated to 60 °C, which yields lifetimes of approximately 5 years for HNBR and 64 years for EPDM for a criterion of 85 % CS respectively, and approx. 40 years for FKM for a criterion of 65 % CS (the highest value measured so far). T2 - Herbsttagung DKG Bezirksgruppe Süd-Südwest CY - Würzburg, Germany DA - 06.10.2016 KW - Rubber KW - Ageing KW - EPDM KW - HNBR KW - FKM PY - 2016 AN - OPUS4-38010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja T1 - Lifetime Prediction of Elastomeric O-Ring Seals N2 - BAM is the federal institute for materials research and testing in Germany. One of our tasks is to evaluate the safety of casks designed for transport and/or storage of radioactive waste. As elastomeric seals are used in the containers as safety-relevant parts, it is our goal to be able to evaluate the service lifetime of the seals with regard to the requirements for long-term safety (40 years and more) of the containers. For this reason, an accelerated ageing programme with selected rubbers often used for seals (HNBR, EPDM and FKM) was started. Ageing was performed at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) for up to 2 years. For assessing properties related to the sealability, O-rings were aged in compression by 25 % (corresponding to the compression during service) between plates. For comparison, uncompressed O-rings were aged as well. The aged materials were characterized with conventional polymer analysis methods such as hardness and tensile tests, but also with more seal-specific methods such as compression stress relaxation (CSR, reflecting the loss of sealing force of a compressed seal over time), and compression set (CS, representing the recovery behaviour of a seal after release from compression). CS is chosen as the property for lifetime prediction as it is both sensitive to degradation and related to the seal performance. CS data is extrapolated to 60 °C, which yields lifetimes of approximately 5 years for HNBR and 64 years for EPDM for a criterion of 85 % CS respectively, and approx. 40 years for FKM for a criterion of 65 % CS (the highest value measured so far). T2 - Vortrag bei der Uni der Bundeswehr CY - Munich, Germany DA - 06.10.2016 KW - Rubber KW - Ageing KW - EPDM KW - HNBR KW - FKM PY - 2016 AN - OPUS4-38007 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja T1 - Lifetime Prediction of Elastomeric O-Ring Seals N2 - The ageing of polymers, including elastomers, is an undesirable but inevitable process leading to a limited lifetime of rubber products such as seals. In order to investigate the degradation of material properties of elastomers used as seals, an ageing programme was started with hydrogenated acrylonitrile butadiene rubber (HNBR), ethylene propylene diene rubber (EPDM) and fluorocarbon rubber (FKM) [1-3]. Sheets of 2 mm thickness were aged at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) for time periods of 1 day up to 1 year. The aged samples were examined using standard analytical methods such as hardness, dynamic-mechanical analysis (DMA), thermogravimetric analysis (TGA), mass loss, density and tensile tests. Additionally, DMA equipment was used to investigate relaxation and recovery behaviour which is more sensitive to degradation effects and can help to correctly interpret data from hardness and DMA measurements. The results show e.g. an increase in hardness and glass transition temperature for HNBR and, less pronounced, for EPDM. This confirms ageing mechanisms described in the literature, e.g. dominant crosslinking reactions in HNBR and both chain scissions and crosslinking for EPDM. FKM, which is very heat resistant, exhibits only minor degradation. Where possible, shift factors for time-temperature data sets were determined. The values obtained from different methods are compared and discussed. T2 - Modification, Degradation and Stabilization of Polymer (MoDeSt) Conference CY - Cracow, Poland DA - 04.09.2016 KW - Rubber KW - Ageing KW - EPDM KW - HNBR KW - FKM PY - 2016 AN - OPUS4-38006 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Long-term behavior of elastomer seals and polymers for neutron shielding N2 - The long time-frame of the necessary safe enclosure of radioactive waste in containers gains interna-tionally an increasing attention. As well extended storage periods as a usually necessary subsequent transportation after storage have to be evaluated. In Germany, the concept of dry interim storage in dual purpose metal casks before disposal is being pursued for spent nuclear fuel (SNF) and high level waste (HLW) management. The initially planned and established dry interim storage license duration of up to 40 years will be too short and its exten-sion will become necessary since there is no repository available in due time. The main safety relevant components are the thick-walled dual purpose metal casks. These casks consist e.g. of a monolithic cask body with integrated neutron shielding components (polymers, e.g. polyethylene) and a monitored double lid barrier system equipped with metal and elastomer seals. The metal seals of this bolted closure system guarantee the required leak-tightness whereas the elastomer seals allow for leakage rate measurement of the metal seals. At BAM we focus on the long-term performance of the sealing system and neutron shielding materials as their application conditions have to be concerned as rather demanding. Therefore, BAM began to investigate the overall function and long-term behavior of elastomer and metal seals and also the irradiation influence on neutron shielding materials. Recently a new project was initiated to expand our investigations to get more and in some context better applicable data. This paper describes the approach of our new research project with the aim of further closure of existing knowledge gaps and presents an overview of investigations concerning the low temperature behavior of elastomer seals, of running long-term tests on elastomer seals at different temperatures under static conditions and the influence of gamma irradiation on neutron shielding materials. T2 - 18th International Symposium on the Packaging and Transportation of Radioactive Materials (PATRAM) 2016 CY - Kobe, Japan DA - 18.09.2016 KW - Aging KW - Irradiation KW - Neutron shielding KW - Elastomer seal PY - 2016 AN - OPUS4-37554 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja T1 - Discoloration effects of high-dose γ-irradiation and long-term thermal ageing of (U)HMW-PE N2 - Two polyethylene types with ultra high (UHMWPE) and high molecular weight (HMWPE), which are used as neutron radiation shielding materials in storage casks for radioactive waste, were subjected to gamma irradiation doses up to 600 kGy and subsequent thermal ageing at 125 °C for up to one year. One material was a medical grade UHMWPE and the other a HMWPE containing an antioxidant. Degradation effects in the materials were characterized using colorimetry, UV-Vis spectroscopy, MIR and FTIR measurements, DSC and, in the case of HMWPE, insoluble content determination. Both materials exhibited a yellowing upon irradiation. The discoloration of UHMWPE disappeared again after thermal ageing, which is why it was attributed to annealable color centers in the form of free radicals entrapped in the crystalline regions of the polymer that recombine during thermal ageing. Furthermore, oxidation species were observed with MIR and FTIR spectroscopy. For HMWPE, the yellowing occurred during both irradiation and thermal ageing and was correlated to antioxidant decomposition. Additionally, black spots were observed after thermal ageing of HMWPE that were attributed to reaction products of antioxidant derivatives and catalyst residues. While only little evidence of oxidation species was found in the light material parts, oxidation is expected to concentrate in the black spots as the catalyst residue promotes hydroperoxide decomposition and thus radical formation that initiate polymer oxidation T2 - Ionizing Radiation and Polymers Conference CY - Giens, France DA - 25.09.2016 KW - Polyethylene KW - Gamma-irradiation KW - Yellowing KW - Degradation PY - 2016 AN - OPUS4-38001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaunich, Matthias ED - Brown, R. ED - Gedde, U. ED - Jaunich, Matthias T1 - Polymer Testing - Editorial N2 - Conferences and trade fairs as meeting points for technical people concerned with testing of polymers. KW - conferences KW - editorial KW - trade fair PY - 2016 DO - https://doi.org/10.1016/j.polymertesting.2016.06.020 SN - 0142-9418 VL - 2016/53 IS - 1 SP - A1 PB - Elsevier Sci Ltd. CY - Oxford, UK AN - OPUS4-37361 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaunich, Matthias T1 - Polymer Testing - Editorial N2 - Thoughts about getting started as Associate Editor for Polymer Testing. KW - Editorial KW - Getting started KW - Polymer Testing PY - 2016 DO - https://doi.org/10.1016/S0142-9418(16)30279-3 SN - 0142-9418 VL - 2016/51 IS - 1 SP - III PB - Elsevier Sci. Ltd. CY - Oxford, UK AN - OPUS4-37362 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Grelle, Tobias A1 - Kömmling, Anja A1 - Wolff, Dietmar A1 - Völzke, Holger ED - Stuke, M. T1 - Long-term evaluation of sealing systems for radioactive waste packages N2 - The investigation of the long-term performance of sealing systems employed in containers for radioactive waste and spent nuclear fuel is one research focus area for division 3.4 “Safety of Storage Containers” at the Bundesanstalt für Materialforschung und -prüfung (BAM). Our investigations comprise investigations on metallic and elastomeric seals and covers experimental investigations to get a database on the component/material behaviour, work on analytical descriptions and numerical analysis. Our aim is to understand the long-term behaviour of the sealing systems for evaluation of their performance during possible extended interim storage and subsequent transportation. T2 - 3rd Workshop on Safety of Extended Dry Storage of Spent Nuclear Fuel CY - Garching, Germany DA - 05.06.2019 KW - Seal performance KW - Rubber seal KW - Metallic seal KW - Ageing PY - 2019 SP - 57 EP - 62 AN - OPUS4-48225 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Jaunich, Matthias A1 - Kömmling, Anja A1 - Wolff, Dietmar ED - Grellmann, W. ED - Langer, B. T1 - Investigations of elastomeric seals – Low temperature performance and aging behavior N2 - Due to their simple and reliable application, elastomers are used for many tasks. Many fields of application like transport, aviation and process technology, entail low temperatures where proper functionality of the employed seals has to be ensured. Therefore, understanding the low temperature behavior of elastomeric seals is important for safe seal operation to restrict the temperature application range. For all areas of application, the question of seal lifetime is also important for replacement or maintenance intervals. The lifetime is especially important in applications that allow no seal replacement. Since the seal can determine the lifetime of storage in such cases, reliable lifetime estimation is necessary for these applications, and requires an extensive knowledge of the specific aging behavior. KW - Seal KW - Rubber KW - Ageing KW - Replacement PY - 2017 SN - 978-3-319-41877-3 SN - 978-3-319-41879-7 DO - https://doi.org/10.1007/978-3-319-41879-7_30 SN - 0933-033X SN - 2196-2812 VL - 247 SP - 431 EP - 443 PB - Springer Verlag AN - OPUS4-41167 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Characterisation of degradation and determination of end-of-lifetime criterion for O-ring seals N2 - The ageing of polymers, including elastomers, is an undesirable but inevitable process leading to a limited lifetime of rubber products such as seals. Independent of the application, as e.g. automotive, piping or container applications, a long lifetime or at least a timely exchange of a seal before occurence of critical failure is desired. In order to investigate the degradation of material properties and to determine the lifetime of elastomers used as seals, an ageing programme was started with hydrogenated acrylonitrile butadiene rubber (HNBR), ethylene propylene diene rubber (EPDM) and fluorocarbon rubber (FKM) [1-3]. Both O-ring seals (uncompressed and compressed by 25 %) with a cord diameter of 10 mm as well as sheets with a thickness of 2 mm were aged at 75 °C, 100 °C, 125 °C and 150 °C for up to two years. The changes of material properties during ageing were characterised for each material using the sheets by means of e.g. dynamic-mechanical analysis and tensile tests, while sealing properties such as compression stress relaxation (CSR), compression set (CS) and leakage rate were determined on O-rings. The experimental results indicate that while material properties, CSR and CS show considerable degradation effects, the static leakage rate stays constant or even decreases before failure occurs quite suddenly at advanced degradation levels. This reveals that static leakage rate has only limited sensitivity for the degradation of the seal material. Our approach to determine a suitable end of lifetime criterion, which involves a partial decompression of the seal during the leakage test, is presented and discussed. T2 - RubberCon 2017 CY - Prague, Czech Republic DA - 23.05.2017 KW - Rubber seal KW - Ageing KW - Leakage PY - 2017 AN - OPUS4-40381 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grelle, Tobias A1 - Wolff, Dietmar A1 - Probst, Ulrich A1 - Jaunich, Matthias A1 - Völzke, Holger T1 - Component and material investigations on metal seals for high level radioactive waste containers N2 - Long-term investigations performed at BAM look to extend the state of knowledge on safety-related components of interim storage containers. Metal seals act as the primary sealing barrier in the bolted double lid closure system of the containers. The behaviour of metal seals has been investigated for ageing times up to 8.5 years and for various temperatures. The main cause for reduction in useable resilience overtime was due to creep deformation of the outer jacket of the seal. KW - Metal seal KW - Radioactive waste containers KW - Creep KW - Long-term behaviour PY - 2018 SN - 1745-2058 SP - 32 EP - 34 PB - Nuclear Institute CY - London AN - OPUS4-48206 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja T1 - Comparison of different test methods for lifetime prediction of O-ring seals N2 - Elastomeric O-ring seals are used in a wide range of applications due to their excellent elasticity. However, like all polymers, elastomers degrade under the influence of e.g. time, temperature, oxygen, radiation and mechanical stress. Especially in applications where a replacement of seals after a certain time is hard or almost impossible, it is important to know the seal lifetime. Therefore, an extensive ageing programme with elastomers made of EPDM, HNBR and other materials was started with the aim of determining suitable methods for accelerated ageing and lifetime prediction. In order to determine the lifetime of polymeric parts, the time-temperature superposition principle is commonly used to shift property changes obtained by accelerated ageing at higher temperatures to lower temperatures. If the shift factors yield a straight line in an Arrhenius diagram, a corresponding activation energy can be determined. However, we have found that the shift factors and thus the predicted lifetime depends on the test method that yielded the shifted data. For example, the shift factor between 125 °C and 150 °C ageing temperature was roughly the same (5/5/4.5 respectively) for hardness, density and maximum of loss factor tan  measured on HNBR, but different for elongation at break (8) and compression set (2.2, excluding DLO-affected data). A possible explanation might be that while the different oxidation reactions proceed with a fixed activation energy, they have differing impact on the measured properties. For example, hardness is lowered by chain scission reactions, and increases by crosslinking reactions during ageing. As usually both chain scission and crosslinking reactions occur during ageing, the measured hardness increase reflects only the net effect of both reaction types. On the other hand, compression set is influenced additively by both reaction types: chain scission leads to an increase of the remaining deformation, as broken chains lose their recovery potential, and crosslinking reactions during ageing fix the compressed geometry, which also leads to less recovery. Thus, compression set reflects the total number of changes in the network and shows degradation effects much faster, which results in lower shift factors and lower activation energy. This phenomenon was observed for EPDM as well. In order to verify our hypotheses and to gain further insights, temperature-dependent oxygen consumption measurements are currently being performed and results will be presented at the conference. The shift factors and activation energy determined by oxygen consumption measurements are expected to be close to the values for compression set. T2 - Polymer Degradation Discussion Group Conference CY - Malta DA - 01.09.2019 KW - Compression set KW - Time-temperature superposition KW - Arrhenius KW - HNBR KW - EPDM KW - FKM KW - Activation energy PY - 2019 AN - OPUS4-48907 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Feldkamp, Martin T1 - Ongoing research & development about metal and elastomer seals at BAM N2 - Packages for the transport and storage of radioactive materials are often sealed with elastomer or metal seals. These seals are basic components to meet the leak tightness criteria for these kind of packages. An overview over ongoing research and development concerning metal and elastomer seals is given in the presentation. Introductions in the fundamental functionality of elastomer and metal seals are presented. Ageing processes are shown for both components regarding to different ageing effects. T2 - IRSN Conference on Safe Transport of Radioactive Material CY - Fontenay aux Roses, France DA - 13.11.2018 KW - Seal KW - Seals KW - Metal seal KW - Elastomer seal KW - Long term investigation KW - Helical spring KW - Aluminum seal KW - Silver seal KW - Component test KW - Useable resilience KW - Leakage rate KW - Compression set KW - Low temperature investigation KW - Ageing KW - Radioactive KW - Transport KW - Storage KW - IAEA PY - 2018 AN - OPUS4-46881 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zaghdoudi, Maha T1 - How to test the Arrhenius validity of elastomers during ageing N2 - The main task of the division "Safety of Storage Containers" at BAM is the safety assessment of storage containers for radioactive waste. A sufficient sealing of bolted lid systems for the safe containment of the waste for transport, storage and disposal is very important. Extensive knowledge of the change of the elastomer’s properties during ageing and the availability of reliable end-of-lifetime criteria is mandatory to guarantee long term safe enclosure. In a long-term test programme over 5 years we have studied the degradation and the change of sealing properties of several elastomers, including EPDM, at four different ageing temperatures (75 °C, 100 °C, 125 °C and 150 °C). Compression stress relaxation (CSR) and compression set (CS) experiments were carried out. It has been found that when the data does not cover a sufficient time frame necessary for the evolution of the degradation of a chosen property, a curvature in the Arrhenius relationship is observed. For CSR, the curvature was observed for samples aged up to 186 days. As for CS experiments, the curvature was detected for sample aged up to 2 years. To cover the possible lack of experimental long-term data at low temperatures, a numerical model for CSR was developed and longer ageing times for the simulation were adopted. A degradation-rate based model for the evolution of degradative processes is proposed. The main advantage of the model is the possibility to quickly validate the interpolation at lower temperatures within the range of slower chemical processes without forcing an Arrhenius straight-line extrapolation. The model was also applied to CS experiments and validated by the 5 years experimental results where the curvature was gone, and the degradation property has followed an Arrhenius relationship. In the figure the contribution of the two degradative processes are shown over CS and CSR respectively. T2 - 2nd advanced material science world congress CY - Online meeting DA - 14.06.2021 KW - Arrhenius KW - Processes KW - Compression set KW - Compression stress relaxation KW - Modelling PY - 2021 AN - OPUS4-52825 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja T1 - Analysis of O-ring seal failure in the context of radioactive waste containers N2 - At BAM, which is a federal institute for materials research and testing in Germany, it is one of our tasks to evaluate the safety of casks designed for transport and/or storage of radioactive material. This includes assessment of elastomeric seals applied in the casks. Besides examining the low-temperature behaviour and irradiation effects of elastomeric seals, it is our goal to estimate the service lifetime of the seals with regard to the requirements for long-term safety (40 years and more) of the containers. Therefore, we started an accelerated ageing programme with selected rubbers often used for seals (HNBR, EPDM and FKM) which are aged at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) up to five years. In order to assess sealability, O-rings were aged in compression by 25 % (corresponding to the compression during service) between plates as well as in flanges that allow leakage rate measurements. For comparison, uncompressed O-rings were aged as well. Further methods characterising seal performance are compression stress relaxation (CSR) reflecting the loss of sealing force of a compressed seal over time, and compression set (CS) which represents the recovery behaviour of a seal after release from compression. Additionally, material properties such as hardness, elastic modulus, glass transition temperature and viscoelastic loss factor as well as relaxation and recovery behaviour are examined in order to understand the underlying ageing mechanisms in each material. For obtaining results closely related to practical conditions, O-rings with a full-scale cord diameter of 10 mm were aged. However, this set-up can lead to heterogeneous aging caused by diffusion-limited oxidation (DLO) effects, resulting in distorted bulk properties such as compression stress relaxation and compression set. However, if DLO-affected data is excluded, extrapolations of CS data are possible using time-temperature shifts and Arrhenius graphs. For selecting an appropriate end-of-lifetime criterion, leakage rate measurements were performed, since leakage rate is the only characteristic directly correlated to the performance of the sealing system. A significant increase in leakage rate was considered as the end of the lifetime. However, the O-rings remained leak tight under static conditions and even exhibited an improved, i.e. decreased leakage rate while other properties already indicated strong deterioration. These tests were extended by seal tests with fast partial decompression. Overall an update will be given on the current investigations and results and the planned activities. T2 - Kautschuk Herbst Kolloquium 2022 CY - Online meeting DA - 08.11.2022 KW - Seal KW - Ageing KW - Compression set PY - 2022 AN - OPUS4-56397 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Voss, Heike T1 - Picosecond laser processing of hierarchical micro-nanostructures on Ti-alloy upon pre- and post-anodization N2 - Recent publications indicate that the order of electrochemical anodization (before or after the laser-processing step) plays an important role for the response of boneforming osteoblasts – an effect that can be utilized for improving permanent dental- or removable bone-implants. For exploring these different surface functionalities, multi-method chemical and structural characterizations were performed for two different characteristic micro-spikes covered by nanometric laserinduced periodic surface structures (LIPSS) on Ti-6Al-4V upon irradiation with nearinfrared ps-laser pulses (1030 nm wavelength, ~1 ps pulse duration, 66 & 80 kHz pulse repetition rate) at two distinct sets of laser fluence and beam scanning parameters. This involves morphological and topographical investigations by scanning electron microscopy (SEM) and white light interference microscopy (WLIM), near-surface chemical analysis by X-ray photoelectron spectroscopy (XPS) and hard X-ray photoelectron spectroscopy (HAXPES), as well as structural material examination via X-ray diffraction (XRD) measurements. The results allow to qualify the laser ablation depth, assess the spike geometry and surface roughness parameters, and provide detailed insights into the near-surface oxidation that may cause the different cell growth behavior for pre- or post-anodized medical implants. T2 - E-MRS Spring Meeting 2023 CY - Strasbourg, France DA - 29.05.2023 KW - Hard X-ray photoelectron spectroscopy (HAXPES) KW - Laser-induced periodic surface structures (LIPSS) KW - Ti6Al4V alloy KW - Hierarchical micro-nanostructures KW - Ultrashort laser processing PY - 2023 AN - OPUS4-60344 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, Mike T1 - Coefficients of Friction in Dependence on Aging State of Elastomers – Experimental Identification and Numerical Simulation of the Experiment N2 - Elastomer seals are mounted as barrier seals in lid systems of containers designed for transport and disposal of negligible heat generating radioactive waste and as auxiliary seals in spent fuel storage and transportation casks (dual purpose casks (DPC)). When the behavior of mounted seals under normal and hypothetical accident conditions of disposal and transport is to be simulated, a comprehensive knowledge of their complex mechanical properties at every state of aging is necessary. In previous works, BAM’s efforts in experimental investigations on specimen artificially aged at different temperatures and times and the implementation of the found results in finite element material models were presented. Additionally, our approaches to reproduce the aging process itself and to extrapolate the results of artificially accelerated aging to longer times were presented. Numerical simulations have shown that the behavior of the seal during mounting and one-sided pressurizing and the resulting performance values such as leakage rate strongly depend on the coefficient of friction (COF) between flange and seal. The friction coefficient, in turn, depends on the aging state of the elastomer material as several publications suggest (see below). Dynamic COF between an exemplary ethylene propylene diene rubber (EPDM) material and a stainless steel ball were determined by using a self-designed linear oscillation tribometer. Unaged and artificially aged EPDM specimen stored for 30 days and 100 days at a temperature of 150 °C were tested. A stainless steel ball (d=10 mm) is brought in contact with the specimen’s surface und loaded by normal forces of 2.5 N, 5 N, 10 N and 20 N. During a reciprocating movement of the EPDM sheet, the horizontal force/friction force is continuously measured, and the COF can be derived. It is well known that friction is a complex phenomenon especially in soft materials. It cannot be excluded that the measured friction force is influenced by additional force components, resulting from the ball’s grooving through the elastomer’s surface. This force depends on the penetration depth of the ball and on the resistance of the elastomer in its different states of aging. The latter results from microstructural changes i.e., chain scission and additional crosslinking that occur during aging which in turn influence the softening or hardening of the material. A finite element (FE) ABAQUS® model was developed to reproduce the measurement process. It should help to better understand the physical mechanisms and to quantify the percentage of measured forces resulting from real friction on the one hand and forces resulting from unintended side effects that could falsify the result on the other hand. The behavior of the elastomer in its different states of aging is reproduced by a FE material model already presented in previous works of BAM. T2 - ASME 2022 Pressure Vessels & Piping Conference (PVP2022) CY - Las Vegas, NV, USA DA - 17.07.2022 KW - Radioactive Waste KW - Elastomers KW - Aging KW - Experiment KW - Seal Behavior KW - Numerical Simulation KW - Leakage Rate KW - Coefficient of Friction PY - 2022 AN - OPUS4-57095 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Cyclic mechanical performance and microstructure evolution of P92 under LCF and TMF conditions N2 - 9-12% Cr ferritic-martensitic stainless steels are widely used as high temperature construction materials in fossil fueled power plants due to their excellent creep and oxidation resistance, but changes in electricity markets during the last two decades have considerably changed the typical working conditions of these facilities. The growing contribution of renewable energy sources in power generation forces most of these plants into flexible operation with frequent load shifts or shutdowns. These cyclic operation profiles constitute a major lifetime issue, raising the question which fundamental processes govern the reaction of ferritic-martensitic steels to cyclic load and temperature variations. The present contribution reports on current findings obtained in a multidisciplinary project funded by German Ministry of Education and Research (BMBF) which combines cyclic mechanical and cyclic oxidation testing of different 9-12% Cr grades with detailed microstructural analyses and related micromechanical modeling. In this contribution, an overview will be given on the results obtained in the mechanical testing programme of the project. Mechanical analyses were carried out on P91 and (mainly) P92 steel grades, particularly looking at softening phenomena and lifetimes obtained in isothermal cyclic loading (low cycle fatigue, LCF), non-isothermal cyclic loading (thermo-mechanical fatigue, TMF), and service-like combinations of fatigue and creep/relaxation periods. For this purpose, cylindrical specimens were extracted from thick-walled steam pipes, orthogonal to the pipe axis, and subjected to strain controlled cyclic loading (± 0.2 to ±0.5 % mechanical strain). Temperature intervals of TMF tests were chosen as either 300-620°C or 500-620°C, resembling so-called warm or hot start conditions of a power plant. The test results will be presented and discussed with a focus on the impact of hold periods during testing (combined creep/relaxation-fatigue conditions) on mechanical softening, lifetime and formation of cracks. The findings will be complemented by results on the modification of the hierarchical ferritic-martensitic microstructure under different loading scenarios. T2 - 4th International Workshop on Thermo-Mechanical Fatigue 2019 CY - Berlin, Germany DA - 13.11.2019 KW - Power plant KW - Tempered martensite ferritic steels KW - Thermo-Mechanical Fatigue KW - Microstructure modification KW - EBSD PY - 2019 AN - OPUS4-50053 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan T1 - Morpho-Chemical Characterisation of Me-TiO2 Nanoparticles for Enhanced Photocatalytical Activity N2 - The conversion of solar energy into electricity and solar fuels is of crucial importance for a green and sustainable future. Water splitting using semiconductor photo-catalysts is considered a sustainable method to produce clean hydrogen (H2) fuel. Nevertheless, H2 photo-production efficiency remains still low, although extensive research works to understand better the mechanisms of the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER) are being carried out. In this respect, TiO2 is a key photoactive material, usually employed with a co-catalyst deposited onto the surface to enhance charge carriers’ separation and catalyze surface charge transfer reactions. The deposition of a co-catalyst on the TiO2 nanoparticle surface represents one successful way to enhance the activity of the photocatalyst through a modification of its surface and redox properties. In this context, high-resolution scanning electron microscopy coupled with elemental analysis by energy-dispersive X-ray spectroscopy (EDS) is fundamental for studying and understanding the effect of the nanoparticle morphology on the functional properties of shape-controlled TiO2 crystals (bipyramides, platelets, and elongated particles). Different types of metal-semiconductor combinations, TiO2 shapes and dopant metals (Ag, Pt, etc) and metal concentrations will be discussed. T2 - ECASIA 2022 CY - Limerick, Ireland DA - 29.05.2022 KW - Titania nanoparticles KW - Photocatalysis KW - Scanning electron microscopy KW - Energy dispersive X-ray spectroscopy PY - 2022 AN - OPUS4-54977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Holger T1 - Research at BAM on Metal Seal Performance and Fuel Rod Integrity N2 - The presentation provides an update on preliminary results from research projects in the area of long term performance of metal seals and fuel rod integrity as safety relevant components of spent fuel transport and storage casks for spent nuclear fuel. T2 - Extended Storage Collaboration Program (ESCP) Winter Meeting 2020 CY - Online meeting DA - 09.11.2020 KW - Metal seal KW - Safety KW - Interim storage KW - Spent nuclear fuel KW - Fuel rod PY - 2020 AN - OPUS4-51615 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Performance of 9-12%Cr steels under cyclic loading and cyclic oxidation conditions N2 - 9-12% Cr ferritic-martensitic stainless steels are widely used as high temperature construction materials in power plants due to their excellent creep and oxidation resistance. The growing share of renewable energy sources in power generation forces many of these plants into more flexible operation with frequent load shifts or shutdowns. These cyclic operation profiles constitute a major lifetime issue. The present contribution reports on current findings obtained in a multidisciplinary project which combines cyclic mechanical and cyclic oxidation testing with detailed microstructural analyses. Mechanical analyses are carried out on P92 and P91 steel grades to give an overview of softening phenomena and lifetimes obtained in isothermal cyclic loading (low cycle fatigue, LCF), non-isothermal cyclic loading (thermo-mechanical fatigue, TMF), and service-like combinations of creep and fatigue periods (creep-fatigue interaction). Oxidation testing focuses on the grades P92 and VM12 with the intention of clarifying the impact of frequent passes through intermediate temperature levels on the kinetics of steam-side oxidation and the characteristics of the evolving oxide scales. An attempt is made to evaluate their composition, strength, integrity and adhesion after up to 250 temperature cycles. Flat coupons as well as curved tube sections are tested to assess the mutual influence of geometry on oxide scale integrity. Complementary microstructural investigations by scanning and transmission electron microscopy plus EBSD are used for phase identification and substrate/oxide interface characterisation. The evolutions of grain size and dislocation density under different test conditions are quantified. T2 - International Conference on Power Plant Operation & Flexibility CY - London, UK DA - 04.07.2018 KW - Ferritic-martensitic steels KW - Low cycle fatigue KW - Thermo-mechanical fatigue KW - Cyclic oxidation PY - 2018 AN - OPUS4-47115 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - A closer look at elastomer O-ring seals - Interesting aspects of these typical machine elements and ways to evaluate their performance - N2 - For many sealing applications rubber O-rings are applied due to their special properties and easy use. In many applications as e.g. in aviation, traffic or process technology the material can be exposed to a variety of conditions during operation as e.g. low temperatures, elevated temperatures and different media. Therefore, it is important to know the material behaviour and the seal performance under those conditions. Additionally ageing of seals is an important factor which has an influence on the long term reliability. In this contribution we would like to discuss different aspects affecting the seal performance, lifetime estimation and address open questions which should be addressed to come to a deeper understanding of these seals commonly understood as typical machine elements. Results of running investigations at the Bundesanstalt für Materialforschung und -prüfung (BAM), Division 3.4 “Safety of Storage Containers” are presented and discussed. T2 - Technomer 2019 CY - Chemnitz, Germany DA - 07.11.2019 KW - Seal KW - Machine element KW - Rubber PY - 2019 AN - OPUS4-49981 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nitz, Phillip D. H. A1 - Rosaz, Paul A1 - Kreysina, Daniela A1 - Kasprzak, Dawid A1 - Qi, Naiyu A1 - Baller, Johannes A1 - Graeber, Gustav T1 - Water-in-Salt Electrolytes Embedded in Polyacrylamide Hydrogels: A First Step toward Deformable Sodium-Ion Batteries N2 - The development of flexible, safe, and sustainable Energy storage systems is critical for next-generation technologies, including wearable electronics, biomedical devices, and soft robotics. In this work, we provide a systematic investigation of sodium perchlorate-based water-in-salt (WIS) electrolytes embedded in polyacrylamide (PAM) hydrogels as a potential platform for deformable sodium-ion batteries or aqueous supercapacitors. Using Raman spectroscopy, we track the transition from free to intermediate water states with increasing salt concentration, identifying the onset of the WIS regime around 10 mol kg−1. Electrochemical measurements reveal that both the aqueous and hydrogel-based electrolytes exhibit a broadened electrochemical stability window (ESW) at higher salt concentrations, reaching up to 2.75 V. Impedance spectroscopy shows that while aqueous electrolytes achieve higher peak conductivity (156 mS cm−1), hydrogel-based electrolytes offer greater stability across a range of concentrations. This observation was supported by cyclic voltammetry, as it showed enhanced electrochemical stability of the PAM hydrogel compared to the aqueous electrolyte. This comprehensive and systematic study demonstrates that highly concentrated WIS electrolytes can be successfullyembedded into PAM hydrogels, while preserving good electrochemical stability and ionic conductivity. This could make them a promising foundation for all-hydrogel, sodium-based energy storage devices that are safe, sustainable, and mechanically compliant. KW - Battery PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653156 DO - https://doi.org/10.1021/acsapm.5c03031 SN - 2637-6105 SP - 1 EP - 8 PB - American Chemical Society (ACS) AN - OPUS4-65315 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Priebe, J. A1 - Radnik, Jörg A1 - Kreyenschulte, C. A1 - Lennox, A. A1 - Junge, H. A1 - Beller, M. A1 - Brückner, A. T1 - H2 Generation with (Mixed) Plasmonic Cu/Au-TiO2 Photocatalysts: Structure–Reactivity Relationships Assessed by in situ Spectroscopy N2 - Monometallic Cu and bimetallic Cu/Au-TiO2 catalysts were prepared by impregnation (IM) and reductive precipitation (RP)methods in sequential (SP) and simultaneous mode (CP) and tested for photocatalytic H2 generation from H2O/Methanol mixtures with visible (400–700 nm) and UV/Vis light (320– 500 nm). Comprehensive studies by high-resolution (HR)-STEM, X-ray photoelectron spectroscopy (XPS), and different in situ methods (X-ray Absorption near-edge structure (XANES), UV/Vis, and EPR spectroscopy) revealed that IM leads to dispersed surface Cu species with no clear particle formation, which is poorly active under visible light, whereas plasmonic Cu0 nanoparticles formed by RP are about three times more active under the same conditions. In Cu/Au-TiO2 catalysts prepared by RP-SP, highly dispersed Cu surface species boost H2 production under UV/Vis light, owing to the effective separation within TiO2 and electron trapping by Cu, whereas small Cu0 and Au0 particles remain widely separated. When Cu/Au-TiO2 catalysts are prepared by RP-CP, mixed Cu/Au particles of uniform size (4–8 nm) provide the highest H2 evolution rates under visible light, owing to effective surface plasmon resonance absorption. KW - Water splitting KW - In situ spectroscopy KW - Photocatalysis PY - 2017 DO - https://doi.org/10.1002/cctc.201601361 SN - 1867-3880 SN - 1867-3899 VL - 9 IS - 6 SP - 1025 EP - 1031 AN - OPUS4-39586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg T1 - Synchrotron radiation as a tool in applied catalytic research N2 - Synchrotron Radiation with its high intensity and the opportunity to tune the wavelength offers unique possibilities to investigate real catalysts, even under industry-like conditions. A good example is a XAFS study performed at supported Ni catalysts used for the dimerization of butene at elevated temperature and pressure. Another example are investigations at titania supported Pd based catalyst elucidating the role of co-components (e.g. Sb, Co, Mn and Au) which are necessary to get the desired promising performance in the gas phase acetoxylation of toluene to benzyl acetate, an environmentally benign alternative for the conventional process using chlorine. Furthermore, investigations about the redox properties of different Cu catalysts will be presented. It could be shown that the redox properties of Cu have a great impact on the performance of such catalysts, not only in some gas phase reactions, but also in photocatalytic applications, e.g. water splitting. T2 - EMIL Seminar CY - Berlin, Germany DA - 23.01.2017 KW - Catalysis KW - Synchrotron radiation KW - Nanochemistriy PY - 2017 AN - OPUS4-39026 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Low temperature performance of rubber seals - Influence of crystallite formation on seal performance N2 - Rubbers are widely used as sealing materials in various applications. In many fields the function of seal materials at low temperatures is necessary. Therefore, the understanding of failure mechanisms that lead to leakage at low temperatures is of high importance. It is known that rubbers possess strongly temperature dependent material properties. At low temperatures high changes in the material properties are observed which can be caused by the rubber-glass transition (abbr. glass transition) or for some rubbers also by partial crystallisation at lower temperatures. During continuous cooling the material changes during rubber-glass transition from rubber-like entropy-elastic behaviour to stiff energy-elastic behaviour. In case of (thermal-) crystallisation the formed crystallites act as additional (physical) crosslinks within the material but the molecules in the amorphous phase can still behave like a rubber. Hence, rubbers are normally used above rubber-glass transition and (thermal-) crystallization temperature but the minimum working temperature limit is heavily depending on the application conditions. Therefore, the lower operation temperature limit of rubber seals is under investigation. In the past we have investigated material properties and sealing behaviour of rubber seals at low temperatures. As the initial work was dedicated to purely static sealing conditions we started to investigate the effect of a small partial release of rubber seals at low temperatures to study the influence of dynamic events on leak tightness. In addition, other groups report on the influence of counterpart surface and adhesion. In this contribution we focus on the difference between purely amorphous elastomers and elastomers which become partially crystalline at low temperatures. The influence of partial crystallization on the low temperature performance of rubber seals is discussed. T2 - Fall Rubber Colloquium 2018 CY - Hannover, Germany DA - 06.11.2018 KW - Seal KW - Low temperature KW - Rubber KW - Partial crystalline PY - 2018 AN - OPUS4-46553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Grelle, Tobias A1 - Goral, Milan A1 - Wolff, Dietmar ED - Gehde, M. ED - Wagenknecht, U. ED - Bloß, P. T1 - Further investigations on the low temperature performance of rubber seals N2 - For many sealing applications low temperature performance is required. The overall understanding of the relevant influences on low temperature performance of rubber seals are summarized and the currently running investigations described. The correlation of the physical material properties with seal performance is studied. This includes as well purely static sealing applications as the performance during/after fast partial relief of seals at low temperatures. T2 - Technomer 2017 CY - Chemnitz, Germany DA - 09.11.2017 KW - Seal KW - Low temperature KW - Rubber KW - Recovery PY - 2017 SN - 978-3-939382-13-3 VL - 2017 SP - 40 EP - 40 AN - OPUS4-42845 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Arfi, W. A1 - Khan, A. A1 - Moulai, F. A1 - Agroui, K. A1 - Baretta, C. A1 - Oreski, G. A1 - Jaunich, Matthias ED - Munday, J. ED - Bermel, P. ED - Kempe, M. T1 - Optical and thermal analysis of PVB encapsulant polymer functionalized with luminescent organic dyes N2 - This work focused on the technology of luminescent down shift (LDS), with a primary aim to identify and investigate a methodology to introduce the luminescent organic dye into PVB polymer encapsulant as emergent material for photovoltaic application. For this goal, we propose to study the feasibility to implement the LDS functionality and to identify suitability of available luminescent to be incorporated into the host polymer encapsulant material. The first step to this direction was through a comprehensive optical study of Violet 570 (V) organic dye in ethanol solvent. The methodology and experimental conditions such as laboratory polymer preparation and luminescence dye concentration were presented. Also, the emergent polymer encapsulant sheets were characterized by using optical and thermal analysis techniques. The absorption spectrum of the prepared PVB material shifts towards longer wavelengths, with increasing organic dye concentration. T2 - New Concepts in Solar and Thermal Radiation Conversion and Reliability CY - San Diego, California, United States DA - 19.08.2018 KW - Photovoltaic KW - Encapsulation KW - Luminescence PY - 2018 SN - 9781510620902 DO - https://doi.org/10.1117/12.2318428 SN - 1996-756X SP - Paper OH, 1 PB - SPIE CY - Bellingham, Washington, USA AN - OPUS4-47165 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Ageing behaviour of elastomer seals N2 - The current results of the ongoing ageing investigations performed at BAM 3.4 are presented. T2 - ElastoMER 2017 CY - Merseburg, Germany DA - 27.09.2017 KW - Ageing KW - Seal KW - Degradation PY - 2017 AN - OPUS4-42476 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sun, F. A1 - Wang, C. A1 - Osenberg, M. A1 - Dong, K. A1 - Zhang, S. A1 - Yang, C. A1 - Wang, Y. A1 - Hilger, A. A1 - Zhang, J. A1 - Dong, S. A1 - Markötter, Henning A1 - Manke, I. A1 - Cui, G. T1 - Clarifying the Electro-Chemo-Mechanical Coupling in Li10SnP2S12 based All-Solid-State Batteries N2 - A fundamental clarification of the electro-chemo-mechanical coupling at the solid–solid electrode|electrolyte interface in all-solid-state batteries (ASSBs) is of crucial significance but has proven challenging. Herein, (synchrotron) X-ray tomography, electrochemical impedance spectroscopy (EIS), time-of-flight secondary-ion mass spectrometry (TOF-SIMS), and finite element analysis (FEA) modeling are jointly used to decouple the electro-chemo-mechanical coupling in Li10SnP2S12-based ASSBs. Non-destructive (synchrotron) X-ray tomography results visually disclose unexpected mechanical deformation of the solid electrolyte and electrode as well as an unanticipated evolving behavior of the (electro)chemically generated interphase. The EIS and TOFSIMS probing results provide additional information that links the interphase/electrode properties to the overall battery performance. The modeling results complete the picture by providing the detailed distribution of the mechanical stress/strain and the potential/ionic flux within the electrolyte. Collectively, these results suggest that 1) the interfacial volume changes induced by the (electro)chemical reactions can trigger the mechanical deformation of the solid electrode and electrolyte; 2) the overall electrochemical process can accelerate the interfacial chemical reactions; 3) the reconfigured interfaces in turn influence the electric potential distribution as well as charge transportation within the SE. These fundamental discoveries that remain unreported until now significantly improve the understanding of the complicated electro-chemo-mechanical couplings in ASSBs. KW - All-solid-state batteries KW - Lithium metal batteries KW - Solid electrolytes KW - Sulfide solid electrolytes KW - Synchrotron X-ray tomography PY - 2022 DO - https://doi.org/10.1002/aenm.202103714 SN - 1614-6832 SP - 2103714 PB - Wiley VHC-Verlag AN - OPUS4-54431 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Göbel, M. A1 - Kirsch, S. A1 - Schwarze, L: A1 - Schmidt, L. A1 - Scholz, H. A1 - Haußmann, J. A1 - Klages, M. A1 - Scholta, J. A1 - Markötter, Henning A1 - Alrwashdeh, S. A1 - Manke, I. A1 - Müller, Bernd R. T1 - Transient limiting current measurements for characterization of gas diffusion layers N2 - The water management in proton exchange membrane fuel cells (PEMFC) is strongly influenced by the design of the gas diffusion layers (GDL). Limiting current measurements in small-scale cells operating at high stoichiometries are useful to determine the oxygen transport resistance. The oxygen transport resistance increases, once water condenses inside the GDL. In this study a new electrochemical method for voltage loss estimation of GDL induced oxygen transport losses are presented. This new method, referred to as “transient limiting current” (TLC), is compared with the literature method. TLC allows a direct estimation of oxygen transport resistance at an arbitrarily conditioned state. This study also presents a case study of liquid water visualization of a PEM fuel cell with varying GDLs types. With the help of quasi in-situ synchrotron X-ray computed tomography and time resolved radiography measurements we investigate appearance and distribution of liquid water inside the GDLs under limiting current conditions. KW - In-situ characterization of GDLs KW - In-situ synchrotron X-ray computed tomography KW - In-situ synchrotron X-ray radiography KW - BAMline PY - 2018 DO - https://doi.org/10.1016/j.jpowsour.2018.09.003 SN - 0378-7753 SN - 1873-2755 VL - 402 SP - 237 EP - 245 PB - Elsevier B.V. AN - OPUS4-46552 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ziesche, R.F. A1 - Hack, J. A1 - Rasha, L. A1 - Maier, M. A1 - Tan, C. A1 - Heenan, T.M.M. A1 - Markötter, Henning A1 - Kardjilov, N. A1 - Manke, I. A1 - Kockelmann, W. A1 - Brett, D.J.L. A1 - Shearing, P.R. T1 - High-speed 4D neutron computed tomography for quantifying water dynamics in polymer electrolyte fuel cells N2 - In recent years, low-temperature polymer electrolyte fuel cells have become an increasingly important pillar in a zero-carbon strategy for curbing climate change, with their potential to power multiscale stationary and mobile applications. The performance improvement is a particular focus of research and engineering roadmaps, with water management being one of the major areas of interest for development. Appropriate characterisation tools for mapping the evolution, motion and removal of water are of high importance to tackle shortcomings. This article demonstrates the development of a 4D high-speed neutron imaging technique, which enables a quantitative analysis of the local water evolution. 4D visualisation allows the time-resolved studies of droplet formation in the flow fields and water quantification in various cell parts. Performance parameters for water management are identified that offer a method of cell classification, which will, in turn, support computer modelling and the engineering of next-generation flow field designs. KW - Neutron imaging KW - Tomography KW - Polymer electrolyte membrane fuel cell PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545978 DO - https://doi.org/10.1038/s41467-022-29313-5 VL - 13 IS - 1 SP - 1616 PB - Nature Publishing Group UK CY - London AN - OPUS4-54597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - John, Sebastian A1 - Auster, Jürgen A1 - Widjaja, Martinus Putra A1 - Duffner, Eric A1 - Mair, Georg W. T1 - NIP II - Forschungsvorhaben „DELFIN“ N2 - Überblick über Projektinhalte und -ergebnisse aus dem Forschungsvorhaben Delfin „Erforschung alternativer Materialien und Fertigungsprozesse für kosten- und gewichtsreduzierte Druckbehälter aus endlosfaserverstärkten Kunststoff“ T2 - SAMPE Kolloquium CY - Online meeting DA - 15.01.2022 KW - Wasserstoff KW - Druckbehälter KW - Impact PY - 2022 AN - OPUS4-58064 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Markötter, Henning T1 - Tomographic Imaging Capabilities with hard X-Rays at BAMline (Bessy II) N2 - The BAMline at the synchrotron X-ray source BESSY II (Berlin, Germany) is supporting researchers especially in materials science. As a non-destructive characterization method, synchrotron X-ray imaging, especially tomography with hard X-Rays, plays an important role in structural 3D characterization. The imaging capabilities allow for in-situ and operando experiments. In this presentation the equipment, data handling pipeline as well as various examples from material science are presented. T2 - Correlative Materials Characterization Workshop 2023 CY - Brno, Czech Republic DA - 09.11.2023 KW - Tomography KW - X-ray imaging KW - Li-ion battery PY - 2023 AN - OPUS4-58958 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - John, Sebastian A1 - Widjaja, Martinus Putra A1 - Mair, Georg W. T1 - Modalanalyse als Werkzeug zur Lebensdauerabschätzung bei Composite-Druckbehältern N2 - Hochbeanspruchte Bauteile wie Druckbehälter bergen im Falle eines Versagens ein erhebliches Gefährdungspotential für Mensch und Umgebung. Trotz der Auslegung mit hohen Sicherheitsfaktoren kommt es durch die hauptsächlich bei mobilen Anwendungen eingesetzten Leichtbauwerkstoffe und Materialkombinationen zu komplexen Degradations- und Schädigungsvorgängen, welche unter ungünstigen Umständen zu einem frühzeitigen Versagen führen können. Die hier vorgestellten Untersuchungen beziehen sich auf Typ IV-Gasspeicher, die als Wasserstofftanks in KFZ zur Anwendung kommen. Durch den Einsatz eines Messverfahrens auf Basis einer experimentellen Modalanalyse (EMA) sollen Schädigungs- und Degradationsgrad künftig zerstörungsfrei erfasst und auch einsatzbegleitend überwacht werden können. T2 - DAGA 2021 - 47. Jahrestagung für Akustik CY - Wien, Österreich DA - 15.08.2021 KW - Impact KW - Modalanalyse KW - Druckbehälter PY - 2021 VL - 47 SP - 1202 EP - 1205 AN - OPUS4-53626 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Okeke, Joseph T1 - In situ and operando imaging, spectroscopy and tomography of batteries N2 - The development of more powerful and more efficient lithium-ion batteries (LIBs) is a key area in battery research, aiming to support the ever-increasing demand for energy storage systems. To better understand the causes and mechanisms of degradation, and thus the diminishing cycling performance and lifetime often observed in LIBs, in operando techniques are essential, because battery chemistry can be monitored non-invasively, in real time. Moreover, there is increasing interest in developing new battery chemistries. Beyond LIBs, sodium ion batteries (NIBs) have gained increasing interest in recent years, as they are a promising candidate to complement LIBs, owing to their improved sustainability and lower cost, while still maintaining high energy density.[1] Initial phases of NIB commercialisation have occurred in the past year. However, for the widespread commercialisation of NIBs, there are still challenges that need to be overcome in developing optimized electrode materials and electrolytes. For the development of such materials and greater understanding of sodium storage mechanisms, solid electrolyte interface (SEI) formation and stability, and degradation processes, in operando methodologies are crucial. Among the techniques available for in operando analysis, nuclear magnetic resonance spectroscopy (NMR) and imaging (MRI) are becoming increasingly used to characterize the chemical composition of battery materials, study the growth and distribution of dendrites, and investigate battery storage and degradation mechanisms. In situ and in operando 1H, 7Li and 23Na NMR and MRI have recently been used to study LIBs and NIBs, identifying chemical changes in Li and Na species respectively, in metallic, quasimetallic and electrolytic environment as well as directly and indirectly studying dendrite formation in both systems.[2-4] The ability of NMR and MRI to probe battery systems across multiple environments can further be complemented by the enhanced spatial resolution of micro-computed X-ray tomography (μ-CT) which can provide insight into battery material microstructure and defect distribution. Here, we report in operando 1H and 7Li NMR and MRI experiments that investigate LIB performance, and the identification of changes in the Li signal during charge cycling, as well as the observation of signals in both 1H and 7Li NMR spectra that we attribute to diminishing battery performance, capacity loss and degradation. Additionally, recent operando methodology are adapted and implemented to study Sn based anodes in NIBs. 23Na spectroscopy is performed to monitor the formation and evolution of peaks assigned to stages of Na insertion into Sn, while 1H MRI is used to indirectly visualize the volume expansion of Sn anodes during charge cycling. Battery operation and degradation is further explored in these NIBs, using μ-CT, where the anode is directly visualized to a higher resolution and the loss of electrolyte in the cell, during cycling is observed T2 - 17th International Conference on Magnetic Resonance Microscopy CY - Singapore DA - 27.08.2023 KW - Sodium ion battery KW - Lithium ion battery KW - NMR KW - MRI KW - Tomography PY - 2023 AN - OPUS4-58421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tang, F A1 - Wu, Z A1 - Yang, C A1 - Osenberg, M A1 - Hilger, A A1 - Dong, K A1 - Markötter, Henning A1 - Manke, I A1 - Sun, F A1 - Chen, L A1 - Cui, G T1 - Synchrotron X-ray tomography for rechargeable battery research: Fundamentals, setups and applications N2 - Understanding the complicated interplay of the continuously evolving electrode materials in their inherent 3D states during the battery operating condition is of great importance for advancing rechargeable battery research. In this regard, the synchrotron X-ray tomography technique, which enables non-destructive, multi-scale, and 3D imaging of a variety of electrode components before/during/after battery operation, becomes an essential tool to deepen this understanding. The past few years have witnessed an increasingly growing interest in applying this technique in battery research. Hence, it is time to not only summarize the already obtained battery-related Knowledge by using this technique, but also to present a fundamental elucidation of this technique to boost future studies in battery research. To this end, this review firstly introduces the fundamental principles and experimental Setups of the synchrotron X-ray tomography technique. After that, a user guide to ist application in battery research and examples of its applications in Research of various types of batteries are presented. The current review ends with a discussion of the future opportunities of this technique for next-generation rechargeable batteries research. It is expected that this review can enhance the reader’s understanding of the synchrotron X-ray tomography technique and stimulate new ideas and opportunities in battery research. KW - 3D imaging KW - Batteries KW - Synchrotron X-Ray KW - Tomography PY - 2021 DO - https://doi.org/10.1002/smtd.202100557 VL - 5 IS - 9 SP - 2100557 PB - Wiley-VCH AN - OPUS4-53394 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Widjaja, Martinus Putra A1 - Joannes, S. A1 - Bunsell, A. A1 - Mair, Georg W. A1 - Thionnet, A. T1 - The Application of a Reduced Volume Method for the Simulation of the Characterisation of a Carbon Fibre Pressure Vessel N2 - The developed model has certain limitations of the element size to be used in the simulation to characterise the strength of composite materials. A reduced volume method is proposed in order to reduce the number of degree of freedom of the finite element simulation.This study has revealed certain configuration to be followed to speed up the computation time. T2 - The 18th European Conference on Composite Materials CY - Athens, Greece DA - 24.06.2018 KW - Composite pressure vessel KW - Fibre break KW - Integral range KW - Representative volume element PY - 2018 SP - 1193-892 AN - OPUS4-48927 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Al-Falahat, A. A1 - Kardjilov, N. A1 - Markötter, Henning A1 - Kupsch, Andreas A1 - Woracek, R. A1 - Alrwashdeh, S. A1 - Manke, I. T1 - Investigation of detector backlighting and other effects in neutron darkfield images N2 - Neutron imaging can provide unique contrast mechanisms. In order to yield reliable and reproducible attenuation coefficients for quantification, one needs to fully understand and characterize the experimental set-up. One effect that has been largely overlooked in scintillator-camera based neutron imaging systems is the backlight scattering or back illumination in the detection system which can significantly affect the quantification of attenuation coefficients and lead to severe errors and image artifacts. Herein, backlighting is investigated by varying the illuminated detector area and the magnitude of the attenuation. The attenuation coefficient of multiple metal plates was determined by polychromatic neutrons bu the CONRAD V7 instrument. The strength of the back illumination strongly depends upon the sample absorption. While it is relatively moderate (a few percent) for weak absorbing samples, it can be severe when the sample is a strong absorber or thick. KW - Attenuation coefficient KW - Neutron imaging KW - Neutron scattering KW - Polycromatic neutrons KW - Scintillator PY - 2024 SN - 1073-9149 DO - https://doi.org/10.1080/10739149.2024.2380772 SP - 1 EP - 11 PB - Taylor & Francis AN - OPUS4-60752 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kömmling, Anja A1 - von der Ehe, Kerstin A1 - Wolff, Dietmar A1 - Jaunich, Matthias T1 - Effect of high-dose gamma irradiation on (U)HMWPE neutron shielding materials N2 - High and ultra-high molecular weight polyethylenes were gamma-irradiated with doses up to 600 kGy. The changes in the material properties were analysed using DSC, DMA, IR spectroscopy, as well as measurements of density and insoluble content. The irradiation led to an increase of the degree of crystallinity because of chain scissions during irradiation, leading to shorter and thus more mobile chains. Both the plateau value of the shear modulus G′ and the insoluble content increased with Irradiation dose, indicating the formation of additional crosslinks. Furthermore, IR spectroscopy revealed irradiation induced oxidation and the formation of double bonds, indicating that some of the hydrogen atoms responsible for the neutron shielding capability have been released. KW - Ultra high molecular weight KW - Polyethylene KW - Gamma irradiation KW - Crosslinking KW - Oxidation PY - 2018 DO - https://doi.org/10.1016/j.radphyschem.2017.02.014 SN - 0969-806X VL - 142 SP - 29 EP - 33 PB - Elsevier AN - OPUS4-42941 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Long-term evaluation of sealing systems for radioactive waste packages N2 - The investigation of the long-term performance of sealing systems employed in containers for radioactive waste and spent nuclear fuel is one research focus area for division 3.4 “Safety of Storage Containers” at the Bundesanstalt für Materialforschung und -prüfung (BAM). Our investigations comprise investigations on metallic and elastomeric seals and covers experimental investigations to get a database on the component/material behaviour, work on analytical descriptions and numerical analysis. Our aim is to understand the long-term behaviour of the sealing systems for evaluation of their performance during possible extended interim storage and subsequent transportation. T2 - 3rd Workshop on Safety of Extended Dry Storage of Spent Nuclear Fuel CY - Garching, Germany DA - 05.06.2019 KW - Seal performance KW - Rubber seal KW - Metallic seal KW - Ageing PY - 2019 AN - OPUS4-48224 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jürgens, Maria A1 - Olbricht, Jürgen A1 - Fedelich, Bernard A1 - Skrotzki, Birgit T1 - FLEXIKON - Teil 2: Ermüdungsverhalten, Schädigungsentwicklung und Lebensdauer von 9-12% Cr-Stählen im zyklischen Kraftwerksbetrieb N2 - Schnelle Lastwechsel führen v.a. in dickwandigen Kraftwerksbauteilen zu starken thermischen und mechanischen Beanspruchungen, da sich hohe Temperaturgradienten über der Wand des Bauteils einstellen. Es ergeben sich komplexe Lastkollektive aus zeitlich veränderlichen Spannungen/Dehnungen und Temperaturen, die formal einer Kombination aus Kriechbeanspruchung, Kriechermüdung und thermomechanischer Ermüdung (TMF) entsprechen. T2 - 47. Kraftwerkstechnisches Kolloquium CY - Dresden DA - 13.10.2015 KW - TMF KW - LCF KW - P91 KW - P92 PY - 2015 AN - OPUS4-35613 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaunich, Matthias A1 - Böhning, Martin A1 - Braun, Ulrike A1 - Teteris, G. A1 - Stark, W. T1 - Investigation of the curing state of ethylene/vinyl acetate copolymer (EVA) for photovoltaic applications by gel content determination, rheology, DSC and FTIR N2 - The cure behaviour of a specific ethylene vinyl acetate material as used for encapsulation of photovoltaic modules was analysed by rheometer, differential scanning calorimetry and Fourier transform infrared spectroscopy to test for a suitable replacement for the laborious determination of gel content. The results show that all applied methods are capable of describing the effects of the cross-linking process. Some provide results very similar to those yielded by analysis of the insoluble content, but the question remains as to whether indirect methods should be preferred over the direct measurement of physical properties, e.g. as performed by the curemeter. A material stored for one year was also tested to demonstrate the effect of extended storage on cure behaviour and how this is detected by different methods. This complements the other methods, which were clearly able to detect the different cure behaviour of the aged EVA, whereas determination of the gel content could not. KW - Photovoltaic cell encapsulation KW - EVA KW - Incoming goods control KW - Insoluble content KW - Rheometer PY - 2016 DO - https://doi.org/10.1016/j.polymertesting.2016.03.013 SN - 0142-9418 VL - 52 IS - 1 SP - 133 EP - 140 PB - Elsevier Ltd. CY - Oxford, UK AN - OPUS4-35918 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Untersuchungen der BAM zum Langzeitverhalten von Metall- und Elastomerdichtungen sowie an Polymeren zur Neutronenmoderation N2 - Ein wesentliches sicherheitstechnisches Kriterium für Transport und Lagerbehälter ist das Langzeitverhalten von verschraubten Deckel-Dichtsystemen unter Verwendung von Metall- und Elastomerdichtungen sowie von im Behälterkörper integrierten Polyethylenen zur Neutronen¬abschirmung. Die ordnungsgemäße Funktion der Metalldichtungen ist Voraussetzung für die Einhaltung der geforderten Dichtheit des Deckelsystems, während die Elastomerdichtungen für die Messung der Leckagerate an den Metalldichtungen benötigt werden. Darüber hinaus kommen Elastomer-dichtungen als Primärdichtungen in Behältern für radioaktive Abfälle mit vernachlässigbarer Wärmeentwicklung zum Einsatz. Zur Bewertung des Dichtungsverhaltens sind die alterungsabhängige verbleibende Rückstellkraft für die Metall- und Elastomerdichtungen sowie die sog. nutzbare Rückfederung bei Metalldichtungen von entscheidender Bedeutung. Für Elastomerdichtungen ist zusätzlich eine radiologisch bedingte Materialdegradation zu bewerten. In Bezug auf das Alterungsverhalten von Polyethylen zur Neutronenabschirmung sind neben zeit- und temperaturabhängigen Materialveränderungen insbesondere auch durch Gammastrahlung induzierte Degradationseffekte wie Wasserstoffabspaltung, Vernetzung und Abbau der Polymer¬moleküle zu berücksichtigen. Über die eigentliche Bewertung der Abschirmeigenschaften hinaus sind somit zusätzlich Auswirkungen von Degradationsprodukten auf andere Behälterkomponenten zu diskutieren. Die an der BAM im Fachbereich 3.4 Sicherheit von Lagerbahältern durchgeführten und aktuell laufenden Untersuchungen werden vorgestellt und diskutiert. T2 - 5. RAM-Behältersicherheitstage CY - Berlin, Germany DA - 16.03.2016 KW - Alterung KW - Dichtung KW - Degradation KW - Zwischenlagerung PY - 2016 AN - OPUS4-35915 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Agroui, K. T1 - Analysis techniques of polymeric encapsulant materials for photovoltaic modules: Situation and perspectives N2 - The properties of the encapsulant are critical to the long-term performance of photovoltaic (PV) modules under the influence of sunlight including UV, elevated temperature, humidity and diffusion of oxygen. Encapsulation process represents about 40% of the whole PV module cost. The introduction of new non-EVA encapsulant material type “Low-Cost, High-Performance” should provide a solution to outdoor yellowing degradation problems. The emerging encapsulant materials exhibit a good compatibility with emerging PV solar cells for long term durability. This new generation of encapsulant materials has the advantage to improve the PV module performances and long term durability for specific climate like desert regions. This scientific contribution presents an overview of the different encapsulant materials currently on the market, the general requirements of the emerging encapsulant materials and characterizations techniques for degradation, diagnostic and reliability lifetime estimation in the framework of Algerian renewable energy strategy. T2 - Africa-EU Symposium on Renewable Energy Research and Innovation CY - Tlemcen, Algeria DA - 08.03.2016 KW - solar cells KW - PV module KW - polymer encapsulant KW - encapsulation KW - analysis techniques PY - 2016 AN - OPUS4-35916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, Mike T1 - Testing and numerical simulation of elastomeric seals under consideration of time dependent effects N2 - Due to delays in the siting procedure to establish a deep geological repository for spent nuclear fuel and high level waste and in construction of the already licensed Konrad repository for low and intermediate level waste, extended periods of interim storage will become more relevant in Germany. BAM is involved in most of the cask licensing procedures and is responsible for the evaluation of cask-related long-term safety issues. Elastomeric seals are widely used as barrier seals for containers for low and intermediate level radioactive waste. In addition they are also used as auxiliary seals in spent fuel storage and transportation casks (dual purpose casks (DPC)). To address the complex requirements resulting from the described applications, BAM has initiated several test programs for investigating the behavior of elastomeric seals. These include experiments concerning the hyperelastic and viscoelastic behavior at different temperatures and strain rates, the low temperature performance down to -40°C, the influence of gamma irradiation and the aging behavior. The first part of the paper gives an overview of these tests, their relevant results and their possible impact on BAM’s work as a consultant in the framework of approval and licensing procedures. The second part presents an approach of the development of a finite element model using the finite element code ABAQUS®. The long-term goal is to simulate the complex elastomeric behavior in a complete lid closure system under specific operation and accident conditions. T2 - ASME 2016 Pressure Vessels & Piping Conference (PVP2016) CY - Vancouver, BC, Canada DA - 17.07.2016 KW - Elastomeric seals KW - Testing KW - Low temperature behavior KW - Aging KW - Simulation KW - Time dependent effects PY - 2016 AN - OPUS4-37048 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Investigations to predict the long term performance of polymeric components of storage casks for radioactive waste N2 - As a Federal institute for materials research and testing it is part of our tasks to evaluate the safety of casks designed for transport and/or storage of radioactive material. This includes the investigation of elastomeric seals and polymeric neutron shielding materials used in the containers. In this contribution we would like to present our research focused on the long term performance and associated changes of material properties of elastomeric seals (e.g. EPDM, FKM) and neutron shielding materials ((Ultra) High Molecular Weight Polyethylene) employed in storage casks. Our approach comprises accelerated ageing investigations at elevated temperatures and to some extent investigations of irradiated materials. As the requirements for the extended use of cables in nuclear power plants and for the long term use of cask components are to a certain extent similar, our work might be of interest for the workshop on “Cables ageing in nuclear power plants; R&D current status and forecast”. T2 - Cables ageing in nuclear power plants; R&D current status and forecast CY - Rez, Czech Republic DA - 24.05.2016 KW - Ageing KW - Lifetime evaluation KW - Rubber seal KW - Neutron shielding KW - Storage cask PY - 2016 AN - OPUS4-36337 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja T1 - Influence of ageing on sealability of HNBR, EPDM and FKM O-rings N2 - At BAM, which is a federal institute for materials research and testing in Germany, it is our responsibility to evaluate the safety of casks designed for transport and/or storage of radio-active material. This includes assessment of the elastomeric seals applied in the containers. Besides examining the low-temperature behaviour of elastomeric seals, it is our goal to evaluate the service lifetime of the seals with regard to the requirements for long-term safety (40 years and more) of the containers. Therefore, we started an ageing programme with selected rubbers (HNBR, EPDM and FKM) which are oven-aged at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) up to 1.5 years. In order to assess sealability, O-rings are aged in compression by 25 % (corresponding to the compression during service) between plates as well as in flanges that allow leakage rate measurements. For comparison, uncompressed O-rings are aged as well. Further methods characterising seal performance are compression stress relaxation (CSR) reflecting the loss of sealing force of a compressed seal over time, and compression set (CS) which represents the recovery behaviour of a seal after release from compression. Many other properties, e.g. hardness or glass transition temperature, are influenced in opposite directions by crosslinking and chain scission reactions during ageing. By contrast, CSR and CS are influenced additively by each reaction type, as crosslinking leads to the formation of network chains that are in equilibrium with the compressed geometry, and broken chains lose their recovery potential and their contribution to the sealing force. The experimental results indicate that while CSR and CS show considerable degradation effects, the leakage rate stays constant or even decreases until shrinkage and the loss of resilience of the aged sample leads to the formation of a leak path. T2 - PolyMerTec 2016 CY - Merseburg, Germany DA - 15.07.2016 KW - Degradation KW - Elastomer KW - Seal KW - Compression PY - 2016 AN - OPUS4-36993 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Use of rubber seals at low temperatures N2 - Rubber is widely used as sealing material in various applications. In many fields the function of seal materials at low temperatures is necessary. Therefore, the understanding of failure mechanisms that lead to leakage at low temperatures is of high importance. It is known that the material properties of rubbers are strongly temperature dependent. At low temperatures this is caused by the rubber-glass transition (abbr. glass transition). During continuous cooling, due to the glass transition the material changes from rubber-like entropy-elastic behaviour to stiff energy-elastic behaviour, that allows nearly no strain or retraction. Hence, rubbers are normally used above their glass transition. But as the minimum working temperature limit of elastomers cannot be defined globally and precisely, the lower operation temperature limit of rubber seals should be determined in dependence of the application conditions and the most relevant material properties. In this paper, wesummarize results of our temperature dependent investigation of seal material properties by classical thermal analysis as Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA), combined with measurements of standardized tests as compression set and the seal performance determined in component tests. To reduce the test time of compression set tests a faster technique was developed and applied. To study the influence of dynamic events on the seal performance and to enhance the understanding of occurring seal failure, a setup for a fast partial seal release was designed. T2 - RubberCon 2016 CY - Tampere, Finland DA - 08.06.2016 KW - O-Ring KW - Compression set KW - Leakage rate KW - Low temperature PY - 2016 AN - OPUS4-36514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hertwig, Andreas T1 - Measurement of Porous TiO2 Layers with spectroscopic ellipsometry – a multi-method study N2 - By means of an effective medium (EMA) based approach, it is possible to use spectroscopic ellipsometry to determine the mixing ratios between air and material in porous dielectrics and calculate a quantitative value of the porosity for these materials. As this method is model-based, it is very difficult to provide a quantitative measure for the accuracy of porosity values determined by this method. Valuable additional information can often be obtained by combining ellipsometry with other complementary methods. In the present study, the ellipsometry results were validated by Electron Probe Microanalysis (EPMA) with the option of layer analysis (by the socalled “STRATAGem” approach), gravimetry, and electron microscopy. We analysed porous TiO2 thin layers synthesised by means of a template synthesis approach (evaporation induced self assembly). Ellipsometry measurements on porous samples are difficult to analyse due to the complexity of the models necessary. Often it is difficult to decide if the measured data contains enough information to successfully determine the target quantities (mixing ratio, dielectric function of the matrix material). One method to decrease the complexity of the fit and therefore use the measurement data most efficiently is a multi-sample analysis. In the present case, multi-sample analysis was used for determining the porosity factors of the individual layers while using one common set of dielectric function values for the matrix in all cases. While the results of the fit analysis in this case can be used to show the feasibility and also the limitations of the multi-method approach, the porosity values themselves show a promising agreement between the independent methods. It can therefore be concluded that determining porosity values with ellipsometry is in accordance to other methods to the level of accuracy provided by the complementary methodologies. T2 - International conference on spectroscopic ellipsometry (ICSE-7) CY - Berlin, Germany DA - 06.06.2016 KW - Spectroscopic Ellipsometry KW - Electron Microscopy KW - Multi-method Metrology KW - Porous Materials KW - Thin Films KW - Titanium Dioxide PY - 2016 AN - OPUS4-37202 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Development of TMF testing – a little look back N2 - This presentation shortly outlines the timescale on which thermal and thermo-mechanical fatigue have developed both in academic research and industry. T2 - 3rd International Workshop on Thermo-Mechanical Fatigue CY - Berlin, Germany DA - 27.04.2016 KW - History KW - Thermal fatigue/shock KW - Thermo-mechanical fatigue PY - 2016 AN - OPUS4-36055 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wolff, Dietmar T1 - Long-term behavior of metal and elastomer seals as well as polyethylene as safety relevant components of transport and storage casks for radioactive materials (LaMEP) N2 - In Germany, the concept of dry interim storage in dual purpose metal casks before disposal is being pursued for spent nuclear fuel (SNF) and high level waste (HLW) management. The main safety relevant components are the thick-walled dual purpose metal casks. These casks consist e.g. of a monolithic cask body with integrated neutron shielding components (polymers, e.g. polyethylene) and a monitored double lid barrier system equipped with metal and elastomer seals. The metal seals of this bolted closure system guarantee the required leak-tightness whereas the elastomer seals allow for leakage rate measurement of the metal seals. This presentation provides an overview of BAM proactive R&D projects related to the long-term behavior and degradation effects of metal seals, elastomer seals and polyethylene used as neutron shielding material. Particular attention is paid to the approach and first results of the third-party-founded research project LaMEP with the aim of further closure of existing knowledge gaps of safety relevant aging effects of such cask components. T2 - Symposium Verlängerte Zwischenlagerung CY - Garching (Munich), Germany DA - 22.06.2017 KW - Metal seals KW - Elastomer seals KW - Neutron shielding material KW - Aging PY - 2017 AN - OPUS4-41312 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jürgens, Maria A1 - Sonntag, Nadja A1 - Olbricht, Jürgen A1 - Skrotzki, Birgit T1 - Cyclic operation performance of 9-12% Cr ferritic-martensitic steels part 1: Cyclic mechanical behavior under fatigue and creep-fatigue loading N2 - The current competitive situation on electricity markets forces power plants into cyclic operation regimes with frequent load shifts and starts/shutdowns. In the present work, the cyclic mechanical behavior of ferritic-martensitic 9-12 % Cr steels under isothermal and thermomechanical loading was investigated for the example of grade P92 material. A continuous softening was observed under all loading conditions. The introduction of hold periods to the applied cycles reduced material lifetime, with most prominent effects at technologically relevant small strain levels. The microstructural characterization reveals a coarsening of the original “martensitic” lath-type microstructure to a structure with polygonal subgrains and reduced dislocation density. The microstructural data forms the input for a physically-based modelling approach, both of which are presented in “Part 2: Microstructural Evolution during Cyclic Loading and its Representation in a Physically-based Micromechanical Model“. T2 - 45. MPA-Seminar CY - Leinfelden-Echterdingen, Germany DA - 01.10.2019 KW - Tempered Martensite Ferritic Steels KW - P92 KW - Low Cycle Fatigue KW - Thermo-Mechanical Fatigue KW - Creep-Fatigue PY - 2019 SP - 75 EP - 79 PB - MPA (Materialprüfungsanstalt Universität Stuttgart) CY - Stuttgart AN - OPUS4-50051 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zaghdoudi, Maha T1 - Oxidative ageing of elastomers: experiment and modelling N2 - During an extensive test programme at the Bundesanstalt für Materialforschung und prüfung, material property changes of EPDM O-rings were investigated at different ageing times and an ageing temperature of 125 °C. To exclude possible diffusion limited oxidation (DLO) effects that can distort the data, IRHD micro hardness measurements were performed over the cross-section of compressed O-rings. Continuous stress relaxation measurements were conducted on samples free of DLO effects. The additional effect of physical processes to irreversible chemical ones during a long-term thermal exposure is quantified by the analysis of compression set measurements under various test conditions. By combining the different experimental methods, characteristic times relative to the degradation processes were determined. On the basis of experimental data, a microphysically motivated model that takes into account reversible and irreversible processes was developed. The parameter identification strategy of the material model is based on our experimental investigations on homogeneously aged elastomer O-rings. The simulated results are in good agreement with the experiments. T2 - ACEX-14th International Conference on Advanced Computational Engineering and Experimenting CY - Malta DA - 04.07.2021 KW - Compression stress relaxation KW - Compression set KW - IRHD micro hardness KW - Modelling PY - 2021 AN - OPUS4-52968 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg T1 - Morphological and surface analytical long-term investigations of a CH3NH3PbI3/TiO2 perovskite solar cell N2 - Long-term investigations over 20 weeks of a organic-inorganic hybrid solar cell with SEM/EDX and XPS will be presented. T2 - Kratos User Meeting 2017 CY - Stuttgart, Germany DA - 17.10.2017 KW - Perovskite solar cell KW - SEM with EDX KW - XPS PY - 2017 AN - OPUS4-42626 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grelle, Tobias A1 - Wolff, Dietmar A1 - Probst, Ulrich A1 - Jaunich, Matthias A1 - Völzke, Holger T1 - Component and material investigations on metal seals for high level radioactive waste containers N2 - In Germany casks for interim storage of spent nuclear fuel and high level radioactive waste are equipped with Helicoflex® metal seals as main sealing barrier of the double lid system. The long-term behaviour of those seals is investigated at Bundesanstalt für Materialforschung und –prüfung (BAM) in order to evaluate the safety function of the containment at different temperatures over storage periods of 40 years or more in case extended interim storage becomes necessary. Long-term investigations have been done for ageing times of up to 8.5 years at temperatures ranging from room temperature to 150 °C. It was found that the seal force and useable resilience decrease over time, which is mainly caused by creep deformation of the aluminium (or silver) outer jacket of the seals. This effect becomes stronger with increasing temperature. The ageing processes of the seal material and the overall seal behaviour is under investigation in order to derive analytical descriptions for the long-term seal performance. Thus, standardized tests on the basic seal materials, with focus on aluminium, and additional investigations on the seals as a component are conducted. The current investigations include compression and tension creep measurements as well as tensile testing. Furthermore, ageing of seal segments provides information on the development of the contact area width, jacket thickness and microstructural changes in dependence of time and temperature. The obtained data are used for the development of material models and an analytical approach to describe and predict the time and temperature dependent sealing behaviour in the long-term. T2 - 11th International Conference on the Transport, Storage and Disposal of Radioactive Materials CY - London, UK DA - 15.05.2018 KW - Metal seal KW - Creep KW - Long-term behavior PY - 2018 SP - 18535, 1 EP - 6 AN - OPUS4-45452 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - An update on metal seal tests performed at BAM and implications for interim storage N2 - The investigation of the long-term performance of sealing systems employed in containers for radioactive waste and spent nuclear fuel is one research focus area for division 3.4 “Safety of Storage Containers” at the Bundesanstalt für Materialforschung und -prüfung. Metallic seals are in use in interim storage casks for used fuel and high active waste. Their change in performance over time is of high importance for maintaining safe enclosure. Therefore, investigations on these systems were started at BAM to get a general understanding of the relevant processes. Our investigations comprise investigations on different parameters which influence the seal performance and the main part is focussed on the time and temperature dependent behaviour. In this contribution an update on the performed tests and their respective results will be given in respect to the overview presented in 2020. The understanding of the long-term behaviour of the sealing systems and the performance evaluation during interim storage and subsequent transportation are our goals. T2 - SEDS-Workshop: Sicherheit der längerfristigen trockenen Zwischenlagerung CY - Garching, Germany DA - 15.05.2024 KW - Metal seals KW - Ageing KW - Leakage rate KW - Creep PY - 2024 AN - OPUS4-60640 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen T1 - Interaction of thermo-mechanical fatigue, creep and cyclic oxidation in 9-12% Cr steels N2 - In recent years, the performance of heat resistant ferritic-martensitic steels under cyclic oxidation and cyclic mechanical loading has gained considerable attention. The growing contributions of renewable energy sources to electricity generation have triggered a shift from continuous (baseload) operation of conventional power plants towards cyclic or “flexible” operation, which is needed to stabilize the electric grids by balancing the highly variable renewable’s input. Compared to the impressive amount of data on isothermal oxidation/corrosion and static mechanical loading (creep) that was compiled over decades, only little and sometimes contradictory information is so far available on the reaction of these alloys to cyclic conditions. The latter may involve frequent transients or holds at intermediate temperatures, as well as shut-downs and start-ups with high temperature rates which result in cyclic mechanical loads (thermo-mechanical fatigue, TMF) and thermo-cyclic oxidation at variable temperature. Our contribution will report on recent findings obtained within the framework of a junior research group which investigates the oxidation and fatigue of the ferritic-martensitic grades P91, P92 and VM12 SHC under thermo-cyclic conditions. Cyclic oxidation tests are carried out in steam using different sample shapes (flat coupons, U-segments and rings taken from heat exchanger tubes). Special attention is paid to changes in the kinetics and the integrity and possible delamination/spalling of the oxide layers. Mechanical tests are carried out on material from real steam pipes with a focus on the softening behaviour and lifetime issues resulting from combined creep/TMF loadings. All experiments are carried out in the 300-620°C regime with temperature and load profiles that resemble typical loading scenarios in power plants and are complemented by detailed microstructural characterisation. T2 - IUTAM-Symposium Multi-scale Fatigue, Fracture & Damage of Materials in Harsh Environments CY - Galway, Ireland DA - 28.08.2017 KW - Low cycle fatigue KW - Thermo-mechanical fatigue KW - Creep-fatigue KW - Steam oxidation KW - Power plants PY - 2017 AN - OPUS4-42654 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mrkwitschka, Paul T1 - Correlative analysis with electron microscopy applied in different operating modes (SEM, STEM-in-SEM and TEM) for the accurate morphological characterisation of non-spherical fine nanoparticles N2 - Electron microscopy applied in different operating modes, e.g., SEM, TEM or STEM-in-SEM, is the gold standard method to investigate the exact size and shape of individual nanoparticles. However, when fine nanoparticles with a non-monodisperse size distribution and non-spherical shapes are analysed, achieving an accurate result is challenging. Deviations in size measurements of more than 10% may occur. Understanding of the contrasts and sensitivities characteristic to the individual operating modes of an electron microscope is key in interpreting and evaluating quantitatively the measurement uncertainties needed for an eventual certification of specific nanoparticles via traceable results. Further, beyond the pure measurement, the other components in the analysis workflow with significant impact on the overall measurement uncertainties are the sample preparation and the image segmentation. In the present study the same areas of selected iron oxide fine nanoparticles (<25 nm) as reference nanomaterial (candidate) prepared on substrate for electron microscopy imaging are analysed correlatively with SEM, STEM-in-SEM and TEM with respect to their size and shape distribution. Individual significant measurement uncertainties are discussed, e.g., the sensitivity of secondary electron detectors of InLens-type to the surface morphology, particularly to the presence of an ultrathin organic coating or signal saturation effects on the particle edges, to electron beam exposure, to surface contamination, or the selection of the threshold for image segmentation. Another goal of this study is to establish a basis of analysis conditions which shall guarantee accurate results when both manual and particularly (semi-)automated segmentation approaches are applied. Advantages as well as limitations of the use of different electron microscopy operating modes, applied individually and correlatively, are highlighted. T2 - E-MRS 2024 Spring Meeting CY - Strasbourg, France DA - 27.05.2024 KW - Nanoparticles KW - Electron Microscopy KW - Metrology KW - Imaging KW - Reference materials PY - 2024 AN - OPUS4-60436 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Investigations on the low temperature performance of rubber seals N2 - For many sealing applications rubbers are applied due to their special material properties and easy use. In many applications as e.g. in aviation, traffic or process technology the material can be exposed to low temperatures during operation. Therefore, it is important to know the material behaviour at those low temperatures to determine the temperature range that allows a safe operation of the seal. In this work, we focus on the behaviour of elastomer seals at low temperatures with regard to potential decrease of leak-tightness or catastrophic seal failure of O-ring rubber seals. This is required as material properties of rubbers are strongly temperature dependent but their temperature application range is not always clearly defined. Based on previous investigations which considered the physical material properties and the seal behaviour under purely static conditions we widen the focus on the sealing performance after a fast partial relief of compressed seals and additional materials. For the investigations, different typical rubber seal materials were used as e.g. fluorocarbon (FKM), ethylene propylene diene (EPDM) and hydrogenated acrylonitrile-butadiene (HNBR) rubber. The correlation of the physical material properties with seal performance is studied. This includes as well purely static sealing applications as the Performance during/after fast partial relief of seals at low temperatures. T2 - Technomer 2017 CY - Chemnitz, Germany DA - 09.11.2017 KW - Seal KW - Rubber KW - Low temperature KW - Recovery PY - 2017 AN - OPUS4-42839 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Kai A1 - Mirabella, Francesca A1 - Knigge, Xenia A1 - Mezera, Marek A1 - Weise, Matthias A1 - Sahre, Mario A1 - Wasmuth, Karsten A1 - Voss, Heike A1 - Hertwig, Andreas A1 - Krüger, Jörg A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan A1 - Bonse, Jörn T1 - Chemical and topographical changes upon sub-100-nm laser-induced periodic surface structure formation on titanium alloy: the influence of laser pulse repetition rate and number of over-scans N2 - Titanium and its alloys are known to allow the straightforward laser-based manufacturing of ordered surface nanostructures, so-called high spatial frequency laser-induced periodic surface structures (HSFL). These structures exhibit sub-100 nm spatial periods – far below the optical diffraction limit. The resulting surface functionalities are usually enabled by both, topographic and chemical alterations of the nanostructured surfaces. For exploring these effects, multi-method characterizations were performed here for HSFL processed on Ti–6Al–4V alloy upon irradiation with near-infrared ps-laser pulses (1030 nm, ≈1 ps pulse duration, 1–400 kHz) under different laser scan processing conditions, i.e., by systematically varying the pulse repetition frequency and the number of laser irradiation passes. The sample characterization involved morphological and topographical investigations by scanning electron microscopy (SEM), atomic force microscopy (AFM), tactile stylus profilometry, as well as near-surface chemical analyses hard X-ray photoelectron spectroscopy (HAXPES) and depth-profiling time-of-flight secondary ion mass spectrometry (ToF-SIMS). This provides a quantification of the laser ablation depth, the geometrical HSFL characteristics and enables new insights into the depth extent and the nature of the non-ablative laser-induced near-surface oxidation accompanying these nanostructures. This allows to answer the questions how the processing of HSFL can be industrially scaled up, and whether the latter is limited by heat-accumulation effects. T2 - 2023 E-MRS Spring Meeting, Symposium L "Making light matter: lasers in material sciences and photonics" CY - Strasbourg, France DA - 29.05.2023 KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser pulses KW - Laser processing KW - Hard X-ray photoelectron spectroscopy (HAXPES) KW - Time-of-flight secondary ion mass spectrometry (ToF-SIMS) PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589902 UR - https://onlinelibrary.wiley.com/doi/full/10.1002/pssa.202300719 DO - https://doi.org/10.1002/pssa.202300719 SN - 1862-6319 VL - 221 IS - 15 SP - 1 EP - 12 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-58990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rossi, Andrea A1 - Alladio, Eugenio A1 - Drobne, Damjana A1 - Hodoroaba, Vasile-Dan A1 - Jurkschat, Kerstin A1 - Kononenko, Veno A1 - Madbouly, Loay Akmal A1 - Mrkwitschka, Paul A1 - Novak, Sara A1 - Radnik, Jörg A1 - Saje, Špela A1 - Santalucia, Rosangela A1 - Sordello, Fabrizio A1 - Pellegrino, Francesco T1 - Publisher correction: Development of a one-pot synthesis of rGO in water by optimizing Tour’s method parameters N2 - This is a publisher's correction to the original article "Development of a one-pot synthesis of rGO in water by optimizing Tour’s method parameters" that was published online on 27th September 2024 in "Scientific reports" (DOI: 10.1038/s41598-024-73606-2). PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617590 DO - https://doi.org/10.1038/s41598-024-77468-6 SN - 2045-2322 VL - 14 IS - 1 SP - 1 PB - Springer Nature CY - London AN - OPUS4-61759 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dang, Thi Thuy Hanh A1 - Seeburg, Dominik A1 - Radnik, Jörg A1 - Kreyenschulte, Carsten A1 - Atia, Hanan A1 - Vu, Thi Thu Ha A1 - Wohlrab, Sebastian T1 - Influence of V-sources on the catalytic performance of VMCM-41 in the selective oxidation of methane to formaldehyde N2 - VMCM-41 catalysts from two different tetravalent Vanadium sources, hydrothermally synthesized after a mild gelation step at room temperature, were used as catalysts for the selective oxidation of methane to formaldehyde. Vanadyl acetylacetonate as VMCM-41 precursor, facilitates highest VOx density with predominance of monomeric and a small portion of low-oligomeric VOx species. It produces CH2O in high yield and the highest space time yield (STYCH2O) reaches 5.3 kgCH2O·kgcat −1·h−1 at 600 °C (rate of formation, rCH2O of 363 h−1). VMCM-41 synthesized from vanadyl sulfate hydrate precursor contains a more significant portion of low-oligomeric species. With a lower V loading, these VOx species are significantly less active resulting in a Maximum STYCH2O of 2.7 kgCH2O·kgcat −1·h−1 at 625 °C (rCH2O of 243 h−1). KW - VOx catalyst KW - Methane KW - Formaldehyde PY - 2018 DO - https://doi.org/10.1016/j.catcom.2017.09.004 SN - 1566-7367 VL - 103 SP - 56 EP - 59 PB - Elsevier Science AN - OPUS4-42820 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jürgens, Maria ED - Skrotzki, Birgit ED - Olbricht, Jürgen T1 - Creep fatigue behavior of P91/P92 N2 - 9-12% Cr ferritic-martensitic stainless steels are widely used as high temperature construction materials in power plants due to their excellent creep resistance and good oxidation resistance. Creep resistance is considered as the primary parameter in material selection for base-load power plants, but the growing share of renewable energy sources in power generation forces many installations into more "flexible" operation with frequent load reductions and shutdowns. Under cyclic operation of power plants, temperature gradients occur especially in thick-walled components. Locally, these gradients lead to complex time- and temperature-dependent loading scenarios which may result in superimposed creep deformation/damage, creep-fatigue and thermo-mechanical fatigue. The combination of different damage processes may seriously reduce the lifetimes of respective components. A fundamental understanding of the damage evolution in ferritic-martensitic steels under combined static and cyclic loading is therefore required. In the present contribution, the creep-fatigue behavior of two different 9% Cr steel grades (P91 and P92) was investigated. Standard creep-tests as well as LCF/TMF tests with hold time have been carried out to study the material behavior of the new loading scenarios. Microstructural investigations help to identify the observed deformation characteristics and the dominating damage mechanisms under different loads. The test programme is complemented by cyclic creep-tests (temperature change) and creep-tests under atmospheres. In a next step, the experimental results will be used for parameter identification of a deformation and lifetime model to predict the material behavior. T2 - ECCC 2017 CY - Düsseldorf, Germany DA - 10.09.2017 KW - Near-service testing KW - Power plant KW - Ferritic-martensitic steels KW - P91 KW - P92 KW - Creep-Fatigue PY - 2017 SN - 978-3-514-00832-8 SP - 1 EP - 5 AN - OPUS4-42270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jürgens, Maria T1 - Thermo-Mechanical Fatigue Behavior of P92 N2 - In the present contribution, the thermo-mechanical fatigue and creep-fatigue behavior of two different 9% Cr steel grades (P91 and P92) was investigated. Standard LCF/TMF-tests as well as near-service loading tests with different hold times have been carried out to study the material behavior of the new loading scenarios. Microstructural investigations help to identify the observed deformation characteristics (like e.g. pronounced softening) and the dominating damage mechanisms under different loads. The test programme is complemented by selected tests on service-aged material which demonstrate possible reactions of older components in existing plants to changes in operation profiles. In a next step, the experimental results will be used for parameter identification of a deformation and lifetime model to predict the material behavior. T2 - LCF08 CY - Dresden, Germany DA - 27.06.2017 KW - Near-service testing KW - Power plant KW - Ferritic-martensitic steels KW - P91 KW - P92 KW - Thermo-Mechanical Fatigue PY - 2017 AN - OPUS4-42267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zaghdoudi, Maha A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Übersicht über laufende Untersuchungen zur Langzeitalterung von Elastomerdichtungen N2 - Eine Aufgabe des Fachbereichs 3.4 Sicherheit von Lagerbehältern der Bundesanstalt für Materialforschung und -prüfung (BAM) ist es, die Sicherheit von Behältern zur Lagerung von radioaktivem Abfall mit vernachlässigbarer Wärmeentwicklung zu bewerten. Da solche Behälter vor der Entsorgung transportiert und gelagert werden, ist während dieser Zeit ein sicherer Einschluss des radioaktiven Inhalts von größter Bedeutung. Zur Abdichtung dieser Behälter sind Elastomer-O-Ringe weit verbreitet. Um für solche, wie auch für viele andere Anwendungen, eine Voraussage über die Lebensdauer dieser Komponenten treffen zu können, ist es unerlässlich zu verstehen, welchen Einfluss der durch Alterung hervorgerufene Abbau auf Dauer auf die Elastomerdichtungen hat. In einem Langzeittest wurden drei Kautschukarten (EPDM und FKM, die für die Anwendung relevant sind, und HNBR als Vergleich) über mehrere Jahre untersucht. Dabei wurden die Veränderungen der mechanischen Eigenschaften (z. B. Härte und Bruchdehnung) bei vier verschiedenen Alterungstemperaturen (75 °C, 100 °C, 125 °C und 150 °C) sowie das Dichtungsverhalten betrachtet. Um den Einfluss von Vernetzung und Kettenspaltung auf die beobachteten Alterungseffekte zu bestimmen, wurden Messungen zur kontinuierlichen und intermittierenden Druckspannungsrelaxation durchgeführt. Dadurch konnten Erkenntnisse über Kinetik und Mechanismus der Abbaureaktionen gewonnen werden. Zur Einschätzung des Dichtungsverhaltens wurden Durckverformungsrest und Leckagerate gemessen. Die Ergebnisse zeigen, dass die O-Ringe unter statischen Bedingungen auch dann dicht halten, wenn die Werte für Druckverformungsrest, Druckspannungsrelaxation und mechanische Eigenschaften schon auf einen fortgeschrittenen Alterungsabbau hindeuten. Aus diesem Grund wurde ein modifizierter Dichtigkeitsversuch mit einer geringen und schnellen teilweisen Entlastung der Dichtung entwickelt, mit dessen Hilfe sich ein Lebensdauerkriterium bestimmen lässt, das eine Sicherheitsspanne für thermische Schrumpfung und Vibrationen beinhaltet. KW - Alterung KW - O-ring KW - Elastomer Dichtung PY - 2020 SN - 0176-1625 VL - 73 IS - 07-08 SP - 326 EP - 332 PB - Gupta CY - Ratingen AN - OPUS4-51207 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zaghdoudi, Maha A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Albouy, P.-A. A1 - Häcker, Ralf A1 - Stock, Daniel T1 - Overview of ongoing research and future prospects on polyethylene neutron shielding materials at bam N2 - The extension of the interim storage period of radioactive waste before disposal will cause additional challenges for the nuclear waste management in Germany, so that an extensive knowledge of the long-term performance of casks, including their components and inventories, will be required for future extended storage licenses. Ultra-high and high molecular weight polyethylenes ((U)HMW-PE) are used for neutron shielding purposes in casks for storage and transport of spent fuel and high-level waste due to their extremely high hydrogen content. During their service life of several decades as cask components, the PE materials are exposed to neutron and gamma radiation from the radioactive inventory of the casks, mechanical assembling stresses and temperature. All these combined effects affect the material properties of such components which in turn may be crucial for some possible accident scenarios. At the Bundesanstalt für Materialforschung und -prüfung (BAM), the effects of high temperature exposure in combination with subsequent or previous irradiation were investigated with a comprehensive aging program including thermal aging at 125 °C for different aging periods up to 5 years and irradiation with doses ranging from 50 to 600 kGy. This contribution provides an overview of the ongoing research related to the structural changes of (U)HMW-PE induced by gamma irradiation and high temperature exposure and focuses on current research perspectives at BAM with regard to the prediction of the dynamic behavior of the material during extended interim storage in case of an accident scenario. First results of the coupled effect of temperature, radiation and mechanical loading will be presented. The effect of microstructural changes induced by gamma irradiation and high temperature on the mechanical behavior of (U)HMW-PE will be assessed. T2 - PATRAM22 CY - Juan-Les-Pins, Antibes, France DA - 11.06.2023 KW - (U)HMWPE KW - Ageing KW - Irradiation KW - WAXD KW - SHPB PY - 2023 SP - 1 EP - 10 AN - OPUS4-57707 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grelle, Tobias T1 - Material investigation and long-term sealing behavior of Helicoflex® metal seals used in containers for spent nuclear fuel N2 - In Germany spent nuclear fuel is stored and transported in casks that possess bolted lid systems equipped with double jacket metal seals of Helicoflex® type in order to enable safe enclosure. A dry interim storage period of 40 years was planned and the casks are licensed for that time. However, due to political reasons and delayed disposal projects this time period is expected to increase significantly. It is therefore necessary to evaluate the long-term sealing behavior of the casks exceeding 40 years of operating time. In this paper, we discuss our approach to investigate the aging behavior of such metal seals, and to predict the long term sealing behavior. Accelerated aging component tests with seals are performed at temperatures up to 150°C to investigate the course of seal force, useable resilience and leakage rate. Even though these tests have already shown a significant decrease in seal force and useable resilience after aging times of less than 1 year, for most seals the leakage rate stayed better than the specified value. However, observation of the leakage rate has to be continued to determine the effect of the influenced seal properties. As a main influence on the seal long-term behavior the increasing permanent deformation of the outer jacket has been recognized. It is made of aluminum or silver which means that the temperatures that are relevant for the aforementioned application in casks lead to creep deformation. For further investigation of seal behavior a comprehensive research program concerning the material characteristics and aging behavior of the individual seal components, with an emphasis on the outer jacket material, has been launched. The aim is to get a better understanding of the time and temperature dependent creep mechanisms and deformation. The examinations are separated into tests on seal segments and tests on standardized specimen. In order to be able to study the aging process, seal segments are compressed in flanges and stored at temperatures ranging from room temperature to 150°C. After defined time intervals the segments are analyzed by using standardized tests including structure investigation and creep tests. The results are compared with the behavior of the basic raw material for the specimen. This is done to ensure the comparability of the thin jacket material and additional material used for standardized tests. Thus, the prediction of component changes after different ageing times at different temperatures can be made. As a result forecasts on the long term seal behavior are intended. T2 - Waste Management Symposia CY - Phoenix, AZ, USA DA - 05.03.2017 KW - Metal seal KW - Creep KW - Long-term behavior PY - 2017 AN - OPUS4-39891 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaunich, Matthias T1 - The average number of references per article published in Polymer Testing over the years N2 - This Editorial is focussed on the changes in the number of references per article published in Polymer Testing from 1980 until today. To set in into context with other changes a comparison with the impact factor of Polymer Testing is presented. KW - Reference KW - Editorial KW - Impact factor KW - Changes with time PY - 2018 DO - https://doi.org/10.1016/j.polymertesting.2018.05.034 SN - 0142-9418 VL - 68 SP - A1 EP - A2 PB - Elsevier AN - OPUS4-45212 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen A1 - Agudo Jácome, Leonardo A1 - Jürgens, Maria A1 - Roohbakhshan, Farshad A1 - Fedelich, Bernard A1 - Skrotzki, Birgit T1 - Cyclic loading performance and related microstructure evolution of ferritic-martensitic 9-12% Cr steels N2 - The current competitive situation on electricity markets forces power plants into cyclic operation regimes with frequent load shifts and starts/shutdowns. In the present work, the cyclic mechanical behavior of ferritic-martensitic 9-12 % Cr steels under isothermal and thermomechanical loading was investigated for the example of grade P92 material. A continuous softening was observed under all loading conditions. The introduction of hold periods to the applied cycles reduced material lifetime, with most prominent effects at technologically relevant small strain levels. The microstructural characterization reveals a coarsening of the original “martensitic” lath-type microstructure to a structure with polygonal subgrains and reduced dislocation density. The microstructural data forms the input for a physically-based modelling approach. T2 - 44th MPA-Seminar CY - Leinfelden/Stuttgart, Germany DA - 17.10.2018 KW - Ferritic-martensitic steels KW - Cyclic loading KW - Microstructure evolution PY - 2018 SP - 259 EP - 265 AN - OPUS4-47118 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Subramani Bhagavatheswaran, E. T1 - Aging study and electrical resistance based stress-monitoring of rubber seals N2 - Elastomer seals are widely used as barrier seals in containers for low and intermediate level radioactive waste. In addition, they are also used in waste fuel storage and transportation casks as auxiliary seals. Depending on the area of use, the rubber materials have to demonstrate proper sealing performance with respect to mechanical, thermal and environmental conditions as well as irradiation during the entire operation period. A fundamental understanding of the structure property relationship and their changes during aging can help to evaluate the long-term sealing performance. In the present study, specific materials are investigated to study the structure-property and seal performance-correlation. Fluoro-elastomer (FKM), silicone rubber (VMQ) and ethylene propylene diene rubber (EPDM) were chosen as base rubbers. Comparable mechanical properties for these seals, especially in terms of a comparable compression behavior were achieved by careful control of base rubber formulation, i.e., by opting for the right filler and its concentration, amount of crosslinking chemicals, and with the assistance of process oils. Moreover, with the same rubber, similar mechanical properties were achieved by varying the filler concentration and crosslinking degree, which shall enable to correlate the particular influence on the structure property dependency of the seals in detail. The materials are investigated under pristine and aged conditions to evaluate the influence of aging, e.g. on the stress relaxation or recovery behavior. These values appear to be suitable parameters to judge the expected sealing performance. Due to the electrically conducting nature of some fillers used to reinforce rubbers (such as carbon blacks, carbon nanotubes (CNTs), Graphene, etc.) it is possible to obtain current information about mechanical and visco-elastic properties by monitoring the electrical conductivity or resistivity. A simple relation that relates electrical resistance with mechanical stress was derived and the stress values were theoretically predicted from the electrical resistance values, which showed good correlation with experimental results. T2 - 192nd Technical Meeting of the ACS Rubber Division CY - Cleveland, OH, USA DA - 09.10.2017 KW - Ageing KW - Structure-property relationship KW - Rubber KW - Seal PY - 2017 AN - OPUS4-42846 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grelle, Tobias T1 - Investigation program for evaluation and prediction of the long-term behaviour of Helicoflex® metal seals N2 - In Germany, for the transport and storage of spent nuclear fuel, casks with double closure lid systems are used, which are equipped with Helicoflex® metal seals. The original interim storage period for these casks was planned to be 40 years. However, recent developments indicate that a storage time of more than 80 years might be necessary. Therefore, the current licensing has to be renewed, which requires extended knowledge of the long-term behaviour of all cask components. At the Bundesanstalt für Materialforschung und -prüfung (BAM), metal seals have been aged at temperatures of up to 150 °C for up to 7 years. At regular intervals the seals have been tested for leakage rate as well as their mechanical properties. From these tests pronounced influence of ageing could be shown which results in the decrease of the seal force and the useable resilience. The main reason attributed to these performance changes is the increasing permanent deformation of the outer seal component due to creep. So far, an explicit analytical description of the long-term behavior that could be used for predictions exceeding the tested ageing times was not suitable. In addition to the component tests that were already conducted, a comprehensive research program has been started. The aim is to gain information applicable for the prediction of the seal behaviour for an extended period of time under a certain temperature regime. The individual seal components are tested regarding different material characteristics including creep, deformation and microstructural properties. The comparability of the material characterization is ensured by comparing the basic raw material of the specimen with the actual component material. Furthermore, detailed examinations of the time and temperature dependent deformation behaviour are realized by ageing seal segments at multiple temperatures for different periods of time and employing standardized tests. By analyzing the newly acquired data in combination with the long-term component tests analytical forecasts of the long-term behavior of the seals are intended. T2 - Annual Meeting on Nuclear Technology (AMNT) CY - Berlin, Germany DA - 16.05.2017 KW - Metal seal KW - Creep KW - Long-term behavior PY - 2017 AN - OPUS4-40956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja T1 - Aging of elastomer seals for nuclear waste containers – Methods and lifetime prediction N2 - At BAM, which is a federal institute for materials research and testing in Germany, it is one of our tasks to evaluate the safety of casks designed for transport and/or storage of radioactive material. This includes assessment of elastomeric seals applied in the casks. One of the aims is to identify a suitable method for estimating the service lifetime of the seals with regard to the requirements for long-term safety (40 years and more) of the containers. Therefore, we started an accelerated ageing programme with selected rubbers often used for seals (HNBR, EPDM and FKM) which are aged at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) for up to five years. In order to assess sealability, O-rings were aged in compression by 25 % (corresponding to the compression during service) between plates as well as in flanges that allow leakage rate measurements. For comparison, uncompressed O-rings were aged as well. In order to understand the underlying ageing mechanisms in each material, material properties such as hardness, density and tensile properties were examined. Additionally, compression set (CS), which represents the recovery behaviour of a seal after release from compression, is measured. For obtaining results closely related to practical conditions, O-rings with a full-scale cord diameter of 10 mm were aged. However, this set-up can lead to heterogeneous ageing caused by diffusion-limited oxidation (DLO) effects especially for HNBR, resulting in distorted bulk properties such as compression set. However, if DLO-affected data is excluded, extrapolations of CS data are possible using time-temperature shifts. For selecting an appropriate end-of-lifetime criterion, leakage rate measurements were performed, since leakage rate is the only characteristic directly correlated to the performance of the sealing system. A significant increase in leakage rate was considered as the end of the lifetime. However, the O-rings remained leak tight under static conditions even though material properties had already degraded strongly. For this reason, a modified, more demanding leakage test involving a fast small decompression of the seal was developed that allowed determining a more conservative end-of-lifetime criterion with a safety margin for EPDM seals. FKM, which is a very heat and oxidation resistant material, exhibited only little degradation, even though it had the smallest activation energy. T2 - Polymers in nuclear applications CY - Espoo, Finland DA - 27.11.2019 KW - rubber KW - leakage KW - degradation KW - HNBR KW - EPDM KW - FKM PY - 2019 UR - https://www.energiforsk.se/media/27280/agingseals_kommling_bam.pdf AN - OPUS4-49918 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zaghdoudi, Maha T1 - Overview of ongoing research and future prospects on polyethylene neutron shielding materials at BAM N2 - The extension of the interim storage period of radioactive waste before disposal will cause additional challenges for the nuclear waste management in Germany, so that an extensive knowledge of the long-term performance of casks, including their components and inventories, will be required for future extended storage licenses. Ultra-high and high molecular weight polyethylenes ((U)HMW-PE) are used for neutron shielding purposes in casks for storage and transport of spent fuel and high-level waste due to their extremely high hydrogen content. During their service life of several decades as cask components, the PE materials are exposed to neutron and gamma radiation from the radioactive inventory of the casks, mechanical assembling stresses and temperature. All these combined effects affect the material properties of such components which in turn may be crucial for some possible accident scenarios. At the Bundesanstalt für Materialforschung und -prüfung (BAM), the effects of high temperature exposure in combination with subsequent or previous irradiation were investigated with a comprehensive aging program including thermal aging at 125 °C for different aging periods up to 5 years and irradiation with doses ranging from 50 to 600 kGy. This contribution provides an overview of the ongoing research related to the structural changes of (U)HMW-PE induced by gamma irradiation and high temperature exposure and focuses on current research perspectives at BAM with regard to the prediction of the dynamic behavior of the material during extended interim storage in case of an accident scenario. First results of the coupled effect of temperature, radiation and mechanical loading will be presented. The effect of microstructural changes induced by gamma irradiation and high temperature on the mechanical behavior of (U)HMW-PE will be assessed. T2 - PATRAM22 CY - Juan-les-Pins, France DA - 11.06.2023 KW - (U)HMWPE KW - Ageing KW - Irradiation KW - WAXD KW - SHPB PY - 2023 AN - OPUS4-57708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja T1 - Aging of elastomer O-rings and PE neutron shielding materials for radioactive waste containers N2 - Our institution BAM in Berlin, Germany is concerned with research and testing of materials in the context of safety in chemistry and technology. Our working group is involved in the licensing procedures of casks for radioactive waste. Besides, we’re doing research on aging and lifetime prediction of elastomer O-rings and investigate degradation and thermal expansion of PE neutron shielding materials. T2 - Polymers in nuclear applications CY - Online meeting DA - 01.12.2021 KW - Rubber KW - Polyethylene KW - Thermal expansion KW - Lifetime KW - Degradation PY - 2021 UR - https://energiforsk.se/media/30631/bam_material_aging_analysis.pdf AN - OPUS4-54191 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liu, Y. T1 - Cooperation in Advanced Technologies Associated with the Back End of Nuclear Fuel Cycle N2 - A Memorandum of Understanding (MOU) between Argonne National Laboratory (Argonne) and the German Bundesanstalt für Materialforschung und -prüfung (BAM) was signed in October 2014. Its objectives are to promote cooperation among scientists and specialists at Argonne and BAM and establish a framework for collaboration in advanced technologies associated with the back end of the nuclear fuel cycle. Collaborative activities involving Argonne and BAM may be implemented through the promotion of joint research activities and scientific workshops and conferences; exchange of technical information; and visits by scientists, specialists, and graduate, postgraduate, and Ph.D. students. The MOU was renewed in January 2020 for another five years. Highlights of the progress and achievements are provided in identified topical areas for collaboration on ageing management guidance, storage, transportation and disposal R&D, joint conference activities, and conclude with the benefits of the MOU in fostering Argonne and BAM collaboration. T2 - 26th International Conference on Structural Mechanics in Reactor Technology - SMiRT 26 CY - Potsdam, Germany DA - 10.07.2022 KW - Nuclear fuel cycle KW - Back end KW - Spent fuel performance KW - Storage KW - Transportation PY - 2022 AN - OPUS4-55862 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Tests of metallic seals at Bam 3.4 performed over more than 15 years N2 - The investigation of the long-term performance of sealing systems employed in containers for radioactive waste and spent nuclear fuel is one research focus area for division 3.4 “Safety of Storage Containers” at the Bundesanstalt für Materialforschung und -prüfung (BAM) in Germany. The time dependant behaviour of metallic seals, which are employed in interim storage casks for used fuel and high active waste, is of high importance for ensuring safe enclosure. Therefore, investigations on these systems were started at BAM to get a general understanding of the relevant processes. Our investigations comprise investigations on different parameters which influence the seal performance and the main part is focussed on the time and temperature dependent behaviour. In this contribution an overview of the performed tests and their respective results will be given. T2 - 5th sealing workshop by Maestral CY - Avignon, France DA - 05.11.2024 KW - Metal seal KW - Aging KW - Interim storage PY - 2024 AN - OPUS4-62048 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, Mike T1 - Reproducing and discussion of mechanisms in the contact area between metallic seals and flange during aging by finite element analysis (FEA) N2 - When the first site-specific interim storage licenses for DPCs (dual purpose casks), loaded with spent nuclear fuel or vitrified high-level waste from reprocessing were issued, a duration of 40 years was considered for interim storage license application and the long-term safety assessment of casks. In the meantime, the availability of a final repository is further delayed by several decades and thus interim storage for more than a century becomes a necessity. To assess the long-term performance of the typically used metal seals (e.g. Helicoflex), consisting of a helical spring (Nimonic), an inner stainless steel liner and an outer liner made from silver or aluminum, several experimental programs were conducted and are still ongoing. The investigated metal seals are typically mounted in mock-up flange systems and stored at increased temperatures to accelerate the aging process. In certain intervals the remaining seal force, the useable resilience and the corresponding leakage rate are determined. BAM has accompanied such programs for many years and started independent investigations in 2009. Although the remaining seal force is often used as “…one of the key parameters regarding sealing performances over time…” the presented results so far have shown that the courses of the leakage rate and the remaining seal force do not always correlate as expected. In 2016 BAM firstly published results of seals with aluminum liners where the measured leakage rate started to rise after a quite short time period (< 1 year) at 150 °C, although the seal force decreased only slightly compared to the previous measurement. After exceeding the required leakage rate of 10-8 Pa*m3/s it decreased again to acceptable values in the further course of aging. With reference to already published works, BAM has developed a new detailed ABAQUS finite-element (FE) model to represent the behavior of the seal mounted in the mock-up flange during aging, mainly characterized by the creeping of the outer liner. The main goal of the numerical simulation is to reproduce and understand the changing distribution of contact stresses (outer liner/flange) during aging and to discuss if and how it could be causative for the observed early breach of the leak tightness criteria and its later recovery. T2 - PATRAM 2025, 21st International Symposium on the Packaging and Transportation of Radioactive Materials CY - San Antonio, Texas, USA DA - 27.07.2025 KW - Finite element analysis KW - Metallic seals KW - Aging KW - Contact area PY - 2025 AN - OPUS4-63883 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sagradov, Ilja T1 - Long-term tests on metal seals using continuous force measurement in compressed state N2 - In Germany, spent fuel and heat generating radioactive waste is stored in casks for transport and storage (DPCs). The storage licenses were granted for up to 40 years. Due to the delay in identifying a final repository site for such radioactive waste, the storage periods are to be extended significantly. The objective of our research work is to collect additional material data for metal seals in order to be able to better assess the long-term safety of the sealing system of the casks for a period of up to 100 years. A principal safety consideration for the DPCs is the long-term performance of bolted lid sealing systems utilizing metal seals to ensure the safe enclosure of the radioactive inventory during interim storage. To assess the sealing behavior, it is necessary to examine the aging-dependent residual restoring force for the metal seals and the usable resilience. By investigating the change in these values as a function of time and temperature, further insight can be gained into the assessment of long-term safety for extended interim storage. In the present study, the restoring force of metal seals with an outer aluminum jacket and a torus diameter of 9.9 mm was measured continuously. For this purpose, a specially designed device equipped with a load cell was used under isothermal conditions. As part of the investigation, the level and rate of decrease of the restoring seal force were recorded over test periods of one and two months. The seal temperature was set to 35 °C, 75 °C, 100 °C, 125 °C, and 150 °C, respectively. A direct correlation was observed between the temperature of the seal, the level of the restoring force after compressing and heating the seal, and the drop-off characteristics of the restoring force. It was found that in our test device the force level immediately after reaching the respective temperature is lower for higher seal temperatures, while the drop rate of the restoring force is higher. This paper describes the experimental setting and discusses first results in comparison with our long-term discontinuous measurements. T2 - 21st International Symposium on the Packaging and Transportation of Radioactive Materials - PATRAM 2025 CY - San Antonio, TX, USA DA - 27.07.2025 KW - Long-Term Safety Assessment KW - Extended Interim Storage KW - Metal Seal Aging KW - Restoring Force Degradation KW - Temperature-Dependent Performance PY - 2025 AN - OPUS4-63880 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Energy Dispersive X Ray Spectrometry (EDS) on GR2Ms for Routine/Standardized Elemental Analysis N2 - The elemental analysis of solid matter by means of the Energy-Dispersive X-Ray Spectrometry (EDS) is meanwhile posible as a quick (seconds!) and more and more accurate analysis via standardsless (instantaneous) quantification. The sensitivity & quantification accuracy for light elements (C, O,..) has significantly increased in the recent years. The availability via table-top SEMs with incorporated EDS is also enhanced. Further, the EDS analysis at an SEM is well-standardized, see ISO/TC 202 Microbeam Analysis & VAMAS/ TWA 37 Quantitative Microstructural Analysis in good liaisonships with ISO/TC 229 Nanotechnologies. It is demostrated that key parameters such as oxygen-to-carbon atomic-% ratio and impurities can be realibly measured, with XPS as a reference method. Various EDS spectrometers and analysis conditions are tested and the validity of the EDS quantification of an ionic liquid of well-defined chemical composition is demonstrated. Next steps are: launch of a corresponding VAMAS interlaboratory comparison and discussions within ISO/TC 202 Microbeam Analysis. T2 - ISO/TC 229 Nanotechnologies Meeting Week CY - Stockholm, Sweden DA - 19.05.2025 KW - Graphene-related 2D materials (GR2M) KW - Energy-Dispersive X-Ray Spectrometry (EDS) KW - Elemental analysis KW - Quantification KW - ISO/TC 229 Nanotechnologies PY - 2025 AN - OPUS4-63190 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jürgens, Maria T1 - Ermüdungsverhalten des warmfesten Stahls P92 N2 - Hochwarmfeste ferritisch-martensitische Stähle mit 9-12 Gew.-% Chromgehalt werden wegen ihrer hohen Kriechfestigkeit und ihres gleichzeitig guten Oxidationswiderstands erfolgreich als Konstruktionswerkstoff für Hochtemperaturbauteile in Kraftwerken eingesetzt. Die zunehmend zyklische Fahrweise konventioneller Kraftwerke im lastflexiblen Betrieb führt zu häufigen Last- und Temperaturwechseln, die von den Bauteilen sicher ertragen werden müssen. Schnelle Lastwechsel verursachen vor allem in dickwandigen Bauteilen erhebliche thermische und mechanische Beanspruchungen. Während unter stationären Betriebs¬bedingungen der Lebensdauerverbrauch von der Werkstoffschädigung durch Kriechen dominiert wurde, verstärkt sich im zyklischen Betrieb die Schädigung durch Ermüdungsprozesse. In der hier vorgestellten Arbeit wird am Beispiel des ferritisch-martensitischen Stahls P92 untersucht, welche Auswirkungen zyklische Fahrweisen auf die Schädigungsprozesse und Lebensdauern dieser Stähle haben. Das Versuchsprogramm kombiniert deshalb Standardtests mit betriebsnahen mechanischen Versuchen unter überlagerter Kriech-, Ermüdungs- und Temperaturwechselbeanspruchung. Diese werden im vorliegenden Beitrag anhand erster Versuchsergebnisse vorgestellt. Ziel der Arbeiten ist, die auftretenden mechanischen Effekte darzustellen und die zugrunde liegenden Schadensmechanismen durch umfangreiche mikroanalytische/fraktographische Nachuntersuchungen des Probenmaterials zu identifizieren. T2 - DGM-AK-Sitzung Mechanisches Verhalten bei hoher Temperatur CY - Berlin, Germany DA - 20.09.2017 KW - P92 KW - LCF KW - RF PY - 2017 AN - OPUS4-42272 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Hagenow, Peter A1 - Kasparek, Eva Maria A1 - Kömmling, Anja A1 - Noack, Volker A1 - Völzke, Holger A1 - Wolff, Dietmar T1 - Requirements for the use of elastomer seals in casks for final disposal of low and intermediate level waste N2 - Elastomer seals are widely used as barrier seals in containers for low and intermediate level radioactive waste and in some countries for spent fuel transportation casks. Depending on the area of use, the rubber materials have to demonstrate proper sealing performance with regard to mechanical, thermal and environmental conditions as well as irradiation during the entire operation period. In Germany the low and intermediate level radioactive waste is planned to be disposed in the Konrad repository in standardized containers. Many of these containers use an elastomer seal between lid and container body. Depending on the radiactive inventory and a possible containment of the waste in inner barrels and/or concrete structures, such containers may require a specific leak tightness. In such cases, specified leakage rates are shall not be exceeded by the the seals to keep potential activity releases from the inventories well below defined limits. Generally, all waste containers have to fulfill the waste acceptance criteria for the Konrad repository as defined by the reports BfS SE-IB-29/08 and SE-IB-30/08. From these criteria several requirements for seal performance are derived. The seals have to: - ensure full functionality until final container disposal, - maintain its function in case of a thermal or mechanical accident, - ensure encapsulation also at -20 °C. This combination of requirements is challenging especially as a seal exchange, which is typical for many other applications, is hardly possible and thus a sound understanding of how to perform safety evaluation of containers is required. Therefore BAM has initiated investigations on elastomer seal behaviour. This work focuses on low temperature behaviour and sealing performance concerning static conditions as well as partial loss of compression and ageing of elastomer seals. Concerning ageing, property changes caused by long-term thermooxidative conditions as well as gamma irradiation are investigated. This contribution presents an overview and explanation of the aims of the ongoing research and gives an update of the most relevant results. T2 - 13th Internationales Symposium "Konditionierung radioaktiver Betriebs- und Stillegungsabfälle CY - Dresden, Germany DA - 22.03.2017 KW - Disposal KW - Konrad repository KW - Seal PY - 2017 SP - 595 EP - 601 AN - OPUS4-39870 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Pourmand, P. A1 - Wolff, Dietmar A1 - Gedde, U.W. T1 - Influence of ageing on sealability of elastomeric O-rings N2 - At BAM, which is the federal institute for materials research and testing in Germany, it is one of our tasks to evaluate the safety of casks designed for transport and/or storage of radioactive material. This includes the assessment of the service lifetime of elastomeric seals that are part of the container lid system with regard to the requirements for long-term safety (40 years and more) of the containers. Therefore, we started an accelerated ageing programme with selected rubbers often used for seals (HNBR, EPDM and FKM) which are aged at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) up to 1.5 years. In order to assess sealability, O-rings are aged in compression by 25 % (corresponding to the compression during service) between plates as well as in flanges that allow leakage rate measurements. For comparison, uncompressed O-rings are aged as well. Further methods characterising seal performance are compression stress relaxation (CSR) reflecting the loss of sealing force of a compressed seal over time, and compression set (CS) which represents the recovery behaviour of a seal after release from compression. Additionally, hardness is measured for information about the change of mechanical properties. The experimental results indicate that while hardness, CSR and CS show considerable degradation effects, the leakage rate stays relatively constant or even decreases until shrinkage combined with the loss of resilience of the aged seal leads to leakage. This demonstrates that static leakage rate, which is the only available direct seal performance criterion, has only limited sensitivity towards the degradation of the seal material. CS data is extrapolated using time-temperature shifts and Arrhenius graphs. An exemplary CS of 50 % would be reached after approx. 1.2, 17 and 29 years at 60 °C for HNBR, EPDM and FKM respectively. T2 - PolymerTec 2016 CY - Merseburg, Germany DA - 15.06.2016 KW - Compression KW - Leakage KW - Degradation KW - Rubber KW - Lifetime PY - 2017 DO - https://doi.org/10.1002/masy.201600157 SN - 1022-1360 SN - 1521-3900 VL - 373 IS - 1 SP - UNSP 1600157, 1 EP - 10 PB - WILEY-V C H VERLAG GMBH CY - Weinheim AN - OPUS4-40958 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Role of Sample Preparation for Accurate and Automated Morphological Analysis of Nanoparticles proven in Interlaboratory Comparison Exercises N2 - Traceable morphological and chemical characterization of nanomaterials with respect to the various possible sizes, size distributions, shapes, and concentrations of real-world nanoparticles (NPs) is a challenging task. Particularly for the nonspherical, non-monodisperse nanoparticles – as typically for most of the commercial particles, including their strong tendency to agglomerate, there is a lack of standard operation procedures providing accurate nanoparticle characterisation. In the framework of the pre-standardisation framework of VAMAS (Versailles Project on Advanced Materials and Standards, www.vamas.org) two interlaboratory comparison (ILC) studies are being carried out under the Technical Working Area (TWA) 34 “Nanoparticle Populations”:i) Project #15 addresses the analysis of the size and shape distribution of TiO2 bipyramidal NPs by traceable imaging methods such as TEM, SEM, STEM-in-SEM, AFM as well as with SAXS as an ensemble method. This ILC is thought as the next level development of the case studies exemplified in the published ISO standards ISO 21363 and ISO 19749. It was agreed to complete the first ILC with the NPs already prepared according to the same procedure on a TEM grid, and, at a later stage, to carry out second ILCs with the same NPs distributed to the participants as liquid suspensions together with protocols for the uniform NP deposition on suited substrates - as developed and optimized within the European project nPSize. Once having good deposition protocols available, the door for automated image analysis gets opened. Corresponding image analysis protocols and reporting templates have been distributed to the ILC participants, too. ii) Project #16: two spherical SiO2 NP samples with bi-modal size distributions in two nominal relative number concentrations were prepared and distributed also as liquid suspensions accompanied by sample preparation, measurement, and image analysis protocols and reporting templates. Here, the NP concentration is the primary parameter to be measured. For the imaging methods it is targeted to measure the relative nanoparticle concentrations (relative populations of the two modes). The results of all the participating laboratories, in both ILCs, compiled in comparative representations will be shown and discussed for the first time. The reduction of the measurement uncertainties associated to the size, shape and number-concentration results induced by the significant improvement of the sample preparation on substrates (as single particles with a high-density coverage), combined with welldefined image analysis procedures will be highlighted. T2 - MaterialsWeek 2024 CY - Limassol, Cyprus DA - 17.06.2024 KW - Nanoparticles KW - VAMAS KW - Interlaboratory comparison KW - Sample preparation KW - Nanoparticle concentration PY - 2024 AN - OPUS4-60453 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - O-ring seals: Material degradation, seal performance and determination of end-of-lifetime criterion N2 - Ageing of O-ring seals to evaluate the probable lifetime is an important task for long term applications. In this contribution the material degradation of O-ring seals is studied and a suitable end-of-lifetime criterion is determined under consideration of the application conditions. T2 - VDI Fachtagung Dichtungstechnik CY - Schweinfurt, Germany DA - 27.06.2017 KW - O ring KW - Ageing KW - Lifetime criterion PY - 2017 AN - OPUS4-40957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Goral, Milan A1 - Wolff, Dietmar T1 - Insights for lifetime predictions of O-ring seals from five-year long-term aging tests N2 - O-rings made of HNBR, EPDM and FKM were aged in the compressed and uncompressed state at 150 °C, 125 °C, 100 °C, 75 °C, 60 °C and 23 °C for aging times of up to five years. Hardness was measured and increased with aging time and temperature for HNBR and EPDM, but it remained practically constant for FKM. Indenter modulus measurements were performed on the lateral O-ring surface (that was free of DLO effects) to assess an influence of the compression during aging, but none was detected. The equilibrium compression set (CS) exhibited faster and stronger degradation than hardness and was used for lifetime predictions using the time-temperature superposition (TTS) principle. With an end-of-lifetime criterion of 70 % CS, lifetimes of 4.5 years, 50 years and 526 years at 75 °C were estimated for HNBR, EPDM and FKM, respectively. The activation energies derived from an Arrhenius plot of the shift factors from the TTS were 85 kJ/mol, 99 kJ/mol and 78 kJ/mol for HNBR, EPDM and FKM, respectively, revealing that a higher activation energy does not necessarily mean that the material has a higher lifetime at lower temperatures. Furthermore, the measured lifetime of EPDM O-rings at 100 °C (5 years) was compared to that predicted on the basis of the lifetime at 150 °C as well as 125 °C using the corresponding shift factors. The error of the prediction was only ± 4 %. However, this precise prediction could only be achieved using the five-year long-term aging data. When using only data from aging times up to 0.5 years and 2 years, the lifetime of EPDM O-rings at 100 °C was underestimated by 31 % and 22 %, respectively. KW - HNBR KW - EPDM KW - FKM KW - DLO KW - Hardness KW - Compression set KW - Rubber KW - Elastomer KW - Degradation PY - 2020 DO - https://doi.org/10.1016/j.polymdegradstab.2020.109278 VL - 179 SP - 109278 PB - Elsevier Ltd. AN - OPUS4-51060 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Kömmling, Anja A1 - Horn, Jutta A1 - Völzke, Holger A1 - Wolff, Dietmar T1 - Long-Term Performance of Elastomer seals - From Aging Tests to Lifetime Estimations N2 - Elastomers show a high versatility which makes them ideal materials for sealing applications in various fields. Especially under changing application conditions the high recovery potential of this class of material is beneficial to compensate temperature or pressure fluctuation, and geometrical changes resulting from mechanical loads in e.g. accident conditions. Out of these reasons elastomers are also used in containers for low and intermediate level radioactive waste and for spent fuel transportation casks. In casks designed for low and intermediate level waste elastomer seals can act as primary seal responsible for the containment function whereas in spent fuel storage and transportation casks (dual purpose casks (DPC)) elastomer seals are used as auxiliary seals to allow leakage rate measurements of metal barrier seals. An inherent prerequisite for this kind of application is the Long time-scale of operation without or with limited possibility of seal replacement. In Germany an interim storage license for DPC`s is typically issued for 40 years, a timeframe which might increase in the future due to challenges of the final repository siting procedure. For low and intermediate level waste, also long time periods are required before final disposal can be achieved. Therefore, the performance of elastomer seals over extended time periods is, as for other applications, of high importance. A typical approach to ensure long-term functionality is to perform accelerated aging tests to calculate an estimated lifetime by assuming e.g. Arrhenius like equations for the timetemperature relationship. This approach requires a suitable end of life criterion considering the application of interest. This often can represent a challenge on its own. As BAM is involved in most of the cask licensing procedures and especially responsible for the evaluation of cask-related long-term safety issues we initiated several test programs for investigating the behavior of elastomer seals. Experiments concerning the low temperature performance down to -40 °C and the influence of gamma irradiation have been started first. Currently the thermal aging behavior of elastomer seals, which is the topic of this contribution, is examined. For our aging investigations we use a broad approach to first determine the property changes in different elastomer materials due to thermo-oxidative aging at elevated temperatures and secondly, we test how the typical methods of lifetime extrapolation can be applied to these results. This Approach enables us to detect and exclude undesired side effects which very often influence lifetime estimations. In this contribution, our recent results are extended. The results show that lifetime estimation based on single material properties can be misleading and therefore a combination of several methods is recommended. T2 - ASME 2018 Pressure Vessels and Piping Conference CY - Prague, Czech Republic DA - 15.07.2018 KW - Seal performance KW - Rubber KW - Ageing PY - 2018 VL - PVP2018 SP - 84631-1 EP - 84631-8 AN - OPUS4-46346 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -