TY - CONF A1 - Weigert, Florian A1 - Resch-Genger, Ute A1 - Würth, Christian T1 - Ensemble and single particle studies of the fluorescence properties of core­shell CdSe nanocrystals with different shells and surface chemistries N2 - The optical properties of semiconductor nanocrystals (SCNC) are controlled by constituent material, particle size, and surface chemistry, specifically the number of dangling bonds favoring nonradiative deactivation, and hence also by particle synthesis. In this respect, the fluorescence properties of coreshell CdSe SCNCs with different shells and surface chemistries were studied on ensemble and single particle level, using steady state and timeresolved fluorometry and confocal microscopy with time correlated single photon counting detection. Special emphasis was dedicated to correlate ensemble photoluminescence (PL) quantum yields and decay kinetics with particle brightness, PL time traces, and the Ontime fraction of the single SCNCs. Additionally, the confocal PL images were correlated with AFM measurements in order to derive the amount of absorbing, yet nonemisssive ”dark” SCNCs, the presence of which leading to an underestimation of ensemble PL quantum yields. The results of this study can help to identify synthetic routes and surface modifications minimizing the fraction of dark SCNC, thereby closing the gap to the ultimate goal of colloidally and photochemically stable SCNCs with a PL quantum yield of close to unity. T2 - FQDots16 CY - Berlin, Germany DA - 05.09.2016 KW - Confocal KW - QY KW - QD KW - SCNC KW - Single molecule KW - AFM PY - 2016 AN - OPUS4-38119 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weigert, Florian A1 - Resch-Genger, Ute A1 - Würth, Christian T1 - Photoluminescence Properties of coreshell CdSe Nanocrystals with Different Shells and Surface Chemistries Derived from Ensemble and Single Particle Measurements N2 - The optical properties of semiconductor nanocrystals (SCNCs) depend on constituent material, particle size, and surface chemistry, with the size of the photoluminescence (PL) quantum yield (QY) and the PL decay kinetics being largely controlled by the number of dangling bonds, which have to be properly passivated for high quality materials. Hence, PL measurements can provide insight not only in SCNC photophysics, yet can be also used for quality control of SCNC synthesis and surface modification. In this respect, steady state and time-resolved fluorometry and confocal microscopy with time correlated single photon counting were used to study the PL properties of core-shell CdSe SCNCs with different shells and surface chemistries on ensemble and single particle level, thereby focusing on a correlation of ensemble PL QY and PL decay kinetics with particle brightness, PL time traces, and the On-time fraction of single SCNCs. Additionally, confocal PL images were correlated with AFM measurements in order to derive the amount of absorbing, yet non-emissive ”dark” SCNCs, the presence of which resulting in an underestimation of ensemble PL quantum yields. The results of this study can help to identify synthetic routes and surface modifications, which minimize the fraction of dark SCNCs. T2 - PicoQuant 22nd International Workshop on Single Molecule and Super-Resolution Microscopy in the Life Sciences CY - Berlin, Germany DA - 14.09.2016 KW - Single molecule KW - SCNC KW - QY KW - AFM KW - Confocal PY - 2016 AN - OPUS4-38121 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja A1 - Chatzigiannakis, Emmanouil A1 - Wachtendorf, Volker A1 - von der Ehe, Kerstin A1 - Jaunich, Matthias A1 - Wolff, Dietmar 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 - CONF A1 - Bradley, I. A1 - Otremba, Frank A1 - Birk, A. M. A1 - Bisby, L. T1 - Novel equipment for the study of pressure vessel response to fire N2 - Pressurisation of full-containment pressure vessels in fire is known to be driven by thermal stratification. The predominant mode of heat transfer to the contents (convection from the shell to the liquid phase) results in formation of „hot“ boundary layers. Sub-cooled boiling may also be present. The warm layer rises to the surface through buoyancy and bubble flow, increasing the surface of the liquid above that of the bulk temperature, and hence driving a pressure rise. For reliable prediction of the complex effects governing vessel pressurization a three-dimensional numerical model is required. Work is being undertaken on such a model by other institutions in cooperation with this project. T2 - ASME 2016 CY - Phoenix, Arizona, USA DA - 11.11.2016 KW - Vessels KW - Novel equipment PY - 2016 AN - OPUS4-38433 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Otremba, Frank A1 - Sklorz, Christian A1 - Simon, Sylvio T1 - A new tank design for Hazmat N2 - Initial studies have shown pre-deformed honeycomb structure pressure vessels to have comparable burst pressure to straight steel vessels. It was shown that honeycomp structured tanks have a higher energy absorption than straight steel tanks. Future studies will investigate optimization of the deformed plate, to determine if increased payloads or a reduced wall thickness can be achieved. T2 - ASME 2016 International Mechanical Engineering Congress and Exposition (ICME 2016) CY - Phoenix, Arizona, USA DA - 11.11.2016 KW - Hazmat KW - Tankdesign KW - Honeycomb structure PY - 2016 AN - OPUS4-38399 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönfelder, Thorsten A1 - Otremba, Frank T1 - Temperature distribution during filling of a composite receptacle N2 - The arrangement of the measuring sensors allowed the capture of air flow induced temperatures and material temperatures on various points of the cylinder body. Four significant temperature levels could be observed: Inside the cylinder (far from the wall, close to the wall), inside the aluminium liner and outer surface. Figure 5 shows the temperature distribution after a regular filling process with a filling time of ten minutes. The temperature sensors T1 - T9 are marked with different colors. The corresponding measurement points are shown in Figure 4. Due to the high thermal conductivity of the aluminum liner the induced temperature peaks are quickly derived. A flow-induced exceeding of the maximum approval temperature is not expected. Regarding the safety assessement the results show that the pressure and temperature profilesmustbe taken into account. T2 - ASME 2016 International Mechanical Engineering Congress and Exposition (IMECE2016) CY - Phoenix, Arizona, USA DA - 11.11.2016 KW - Distribution during filling KW - Type III composite pressure receptacles PY - 2016 AN - OPUS4-38404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Chatzigiannakis, Emmanouil A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Schulze, Dietmar A1 - Wolff, Dietmar T1 - Influence of composition on the thermal ageing behaviour of EPDM N2 - Ethylene-propylenene-diene copolymer rubbers (EPDM) are used in a wide range of sealing applications e.g. in automotive industry or in containers for dangerous goods. Investigations with regard to the ageing behavior and lifetime prediction of commercial EPDM rubber seals consisting of 48 % polypropylene (PP) and 4.1 % of 5-ethylidene-2-norbornene (ENB) were conducted [1]. However, structural parameters (monomer ratio, diene type, curing agent etc.) and additives (filler, plasticizer etc.) are known to affect the ageing behavior of rubber compounds [2, 3]. The aim of the current study was to elucidate the influence of each component on the overall deterioration of material properties after thermal ageing. Therefore, different EPDM mixtures were prepared at BAM, the reference being an EPDM with 48 % PP and 4.1 % ENB reinforced with Sillitin. Five more formulations were prepared in order to assess the effect of (i) filler type (carbon black or sillitin), (ii) curing agent (sulfur or peroxide), (iii) plasticizer, (iv) ethylene-propylene ratio and (v) ENB content. Initially, the properties of the unaged materials were investigated by tensile testing, hardness and density measurements, TGA, DSC and DMA. Sulfur vulcanization resulted in higher elongation at break due to the flexibility of the sulfidic crosslinks. Carbon black resulted in better reinforcement compared to Sillitin. A higher ethylene and ENB content lead to higher hardness due to higher crystallinity and higher crosslink density, respectively. Thermal ageing for up to 30 days (with 10 days intervals) took place in circulating hot air ovens at 125 °C. Pronounced crosslinking was found to take place in all peroxide-cured materials, as the unreacted double bonds of the ENB units acted as starting points for oxidation and crosslinking. Increasing the ethylene content resulted in an increase in the ageing resistance of EPDM. This improvement was attributed to the higher crystallinity that inhibits oxygen diffusion and to the smaller number of chain scissions which occur in the PP units. Although significant loss of the plasticizer was observed, the remaining plasticizer adequately improved the tensile properties of the material. The filler type did not significantly affect the ageing behavior of EPDM. Finally, the lower thermal stability of the sulfidic crosslinks resulted in desulfurization and, thus, in an increase in the crosslinking density. To sum up, it has been shown that the monomer composition, curing agent and additives used in EPDM formulations greatly influence the properties and ageing resistance of these materials. T2 - 12. Kautschuk Herbst Kolloquium CY - Hanover, Germany DA - 22.11.2016 KW - Degradation KW - Elastomer KW - Compound PY - 2016 AN - OPUS4-38484 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stegemann, Robert A1 - Cabeza, Sandra A1 - Lyamkin, Viktor A1 - Bruno, Giovanni A1 - Wimpory, Robert A1 - Boin, Mirko A1 - Pittner, Andreas A1 - Kuffel, Mareike A1 - Kreutzbruck, Marc T1 - Characterization of residual stress state by neutron diffraction and residual magnetic field mapping N2 - Based on the residual stress characterization of tungsten inert gas welded S235JRC+C plates by means of neutron diffraction, the evaluation of residual stress with high spatial resolution GMR (giant magneto resistance) sensors is discussed. The experiments performed indicate a correlation of residual stress changes and local residual magnetic stray fields. T2 - Eighth Joint BER II and BESSY II User Meeting CY - Berlin, Germany DA - 07.12.2016 KW - Residual stress KW - Magnetic stray fields KW - GMR KW - Neutron diffraction PY - 2016 AN - OPUS4-38676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mishurova, Tatiana A1 - Cabeza, Sandra A1 - Bruno, Giovanni A1 - Artzt, Katia A1 - Haubrich, J. A1 - Requena, G. T1 - Surface residual stresses analysis in SLM Ti–6Al–4V bridges N2 - Selective Laser Melting (SLM) technique allows to produce parts with complex geometry. Due to the rapid solidification and heat gradient during production, SLM results in presence of residual stress. The present study shows the influence of manufacturing parameters on surface residual stress of Ti-6Al-4V SLM parts. High tensile stresses in the front surface are found. Heat Treatment conditions relax residual stresses almost to zero. High scanning speed during manufacturing results in higher tensile stresses in the surface. T2 - HZB User Meeting CY - BESSY II, Berlin, Germany DA - 08.12.2016 KW - Additive manufacturing KW - Residual stress KW - Selective laser melting PY - 2016 AN - OPUS4-38657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cabeza, Sandra A1 - Mishurova, Tatiana A1 - Kromm, Arne A1 - Nadammal, Naresh A1 - Bruno, Giovanni T1 - Residual stress characterization of IN718 part obtained by selective laser melting N2 - Additive Manufacturing (AM) by Selective Laser Melting (SLM) offers ample scope for producing geometrically complex parts as compared to the traditional subtractive manufacturing strategies. However, the residual stresses developed during the processing can reduce the load bearing capacity as well as induce unwanted distortion, limiting the application of SLM parts. IN718 manufactured by SLM process can show high tensile residual stresses in the surface as high as the yield strength of the wrought alloy. On the other hand, residual stresses in the bulk Show considerably lower stress values, even in compression, indicating a stress re-distribution during deposition of the SLM layers. T2 - HZB User meeting CY - BESSY II, Berlin, Germany DA - 08.12.2016 KW - Additive manufacturing KW - Residual stress KW - Selective laser melting KW - Neintron diffraction PY - 2016 AN - OPUS4-38660 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fischer, Franziska A1 - Kulla, Hannes A1 - Emmerling, Franziska A1 - Rademann, K. T1 - In situ investigation of the mechanochemical formation of cocrystals unsing combined PXRD and Raman spectroscopy N2 - We present an in situ investigation of the mechanochemical formation of cocrystals using synchrotron XRD and Raman spectroscopy. This combination allows to study milling processes on the level of the molecular and crystalline structure thus obtaining reliable data for mechanistic studies. Thereby, mechanochemical syntheses can be optimized to isolate new crystal structures. T2 - Joint BER II and BESSY II User Meeting 2016 CY - Berlin, Germany DA - 07.12.2016 KW - Intermediate KW - Mechanochemistry KW - Cocrystal KW - In situ KW - Milling PY - 2016 AN - OPUS4-38722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Akhmetova, Irina A1 - Wilke, Manuel A1 - Emmerling, Franziska A1 - Rademann, K. T1 - In situ investigation of mechanochemical syntheses of metal phosphonates N2 - We report on the in situ investigation of mechanochemical syntheses of metal phosphonates. The metal phosphonates are formed in milling reactions starting from a metal acetate and a phosphonic acid. The conversions are observed by synchrotron PXRD and Raman spectroscopy to shed light on the reaction mechanisms including possible intermediates. T2 - 8th HZB User Meeting CY - Berlin, Germany DA - 07.12.2016 KW - Mechanochemistry KW - In situ KW - Metal phosphonates KW - XRD KW - Raman spectroscopy PY - 2016 AN - OPUS4-38780 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Naghib-zadeh, Hamid A1 - Güther, Wolfgang A1 - Rabe, Torsten T1 - High-strength and gas-tight ceramic-ceramic joints by RAB composite tapes N2 - Ceramic components with complex shape cannot be produced frequently by usual ceramic forming and sintering processes. Therefore, numerous joining methods were developed and introduced in industrial scale. Nowadays, multi-stage Mo-Mn-process and active brazing are preferentially used, if temperature-stable and gastight joints are required. Unfortunately, both processes involve cost-intensive thermal processes: hydrogenous atmosphere is essential for metallization in Mo-Mn-process and active brazing takes place under vacuum. Thermal processes can be drastically simplified by using Reactive Air Brazing (RAB). Joining under air atmosphere is an interesting alternative, especially to join oxide ceramic components among themselves. So far, main disadvantage of RAB is low strength of join connections. Aim of this investigation was the development of high-strength, thermal shock resistant and gastight ceramic-ceramic joints by RAB. Therefore, - commercial, silver and copper oxide containing RAB soldering composition was modified by addition of ceramic particles with low thermal expansion coefficients (TEC). Hence, thermal misfit between TEC of solder and ceramic components was significantly reduced. - RAB soldering paste was replaced with newly developed RAB composite tapes, produced by ceramic “doctor blade” technology. Thereby, improved potential exist to tailor the brazing layer relating to composition, thickness and thickness uniformity. Gastight alumina-alumina, alumina-zirconia and zirconia-zirconia joints with strongly improved strength were produced by novel composite tapes. No strength degradation of joints was observed after thermal cycling up to 700°C. T2 - Jahrestagung der Deutschen Keramischen Gesellschaft (DKG) 2016 CY - Freiberg, Germany DA - 07.03.2016 KW - Brazing KW - Compsite tapes KW - Ceramic-ceramc joints PY - 2016 AN - OPUS4-36114 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Derra, U. A1 - Mescheder, H. A1 - Winands, K. A1 - Emonts, C. A1 - Comanns, P. A1 - Krüger, Jörg A1 - Kirner, Sabrina A1 - Skoulas, E. A1 - Tsibidis, G.D. A1 - Stratakis, E. T1 - Mimicking lizard-like surface structures upon ultrashort laser pulse irradiation of inorganic materials N2 - The wetting behavior of material surfaces can be controlled by surface structures. We functionalized inorganic material surfaces, such as steel, titanium alloy and silicon, to modify the wetting behavior using ultrashort laser pulses (fs- to ps-range). The laser processing was performed by scanning the laser beam across the surface of initially polished flat sample material. A combined experimental and theoretical study of the laser processing parameters (peak fluence, scan velocity, line overlap) allowed the identification of different regimes associated with characteristic surface morphologies (laser-induced periodic surface structures, grooves, micro cones, dimples, etc.). Analyses of the surface using optical as well as scanning electron microscopy allowed the identification of morphologies providing the optimum similarity to the natural skin of lizards. For mimicking skin structures of moisture-harvesting lizards towards an optimization of the surface wetting behavior, additionally, a two-step laser processing strategy was established for realizing hierarchical micro- and nanostructures. In this approach, a laser-generated regular array of small dimples was superimposed (step 2) to the micron-scaled capillaries processed before (step 1). Optical focus variation imaging measurements finally revealed the three dimensional topography of the laser processed surfaces derived from lizard skin structures. The functionality of these surfaces was analyzed in view of wetting properties. T2 - E-MRS 2016 Spring Meeting, Symposium C: "Laser-material interactions for tailoring future applications" CY - Lille, France DA - 02.05.2016 KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Steel KW - Lizard KW - Wetting PY - 2016 AN - OPUS4-36047 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Koter, Robert A1 - Hartelt, Manfred A1 - Spaltmann, Dirk A1 - Kirner, Sabrina A1 - Pentzien, Simone A1 - Höhm, S. A1 - Rosenfeld, A. A1 - Krüger, Jörg T1 - Tribological properties of femtosecond laserinduced periodic surface structures on metals N2 - Laser-induced periodic surface structures (LIPSS, ripples) were generated on steel and titanium surfaces upon irradiation with multiple linear polarized femtosecond laser pulses (pulse duration 30 fs, central wavelength 790 nm). The experimental conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning geometry for the processing of large surface areas covered homogeneously by the nanostructures. The irradiated surface regions were subjected to optical microscopy (OM), white light interference microscopy (WLIM) and scanning electron microscopy (SEM) revealing sub-wavelength spatial periods. The nanostructured surfaces were tribologically tested under reciprocal sliding conditions against a sphere of hardened 100Cr6 steel at 1 Hz using paraffin oil and engine oil as lubricants. After 1000 sliding cycles at a load of 1.0 N, the corresponding wear tracks were characterized by OM and SEM. For specific conditions the laser-generated nanostructures endured the tribological treatment. Simultaneously, a significant reduction of the friction coefficient was observed in the laser-irradiated (LIPSS-covered) areas when compared to the non-irradiated surface, indicating the potential benefit of laser surface structuring for tribological applications. T2 - SPIE Photonics West Conference, Symposium "Laser Applications in Microelectronic and Optoelectronic Manufacturing" (LAMOM) XXI CY - San Francisco, CA, USA DA - 13.02.2016 KW - Femtosecond laser ablation KW - Laser-induced periodic surface structures (LIPSS) KW - Tribology KW - Friction KW - Wear PY - 2016 AN - OPUS4-36041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kirner, Sabrina A1 - Bonse, Jörn A1 - Koter, Robert A1 - Spaltmann, Dirk A1 - Pentzien, Simone A1 - Krüger, Jörg T1 - Femtosecond laser-induced periodic surface structures on titanium nitride coatings for tribological applications N2 - Laser-induced periodic surface structures (LIPSS) were generated on titanium nitride (TiN) hardcoating surfaces (deposited on metallic substrates) upon irradiation with multiple linearly polarized femtosecond laser pulses in air (30 fs duration, 790 nm wavelength, 1 kHz pulse repetition rate). The conditions were optimized in a sample-scanning geometry for the processing of large surface areas (5 mm x 5 mm) covered homogeneously by nanostructures with sub-wavelength periods ranging between ~200 nm and 700 nm. For these nanostructures the coefficient of friction was characterized under reciprocating sliding condition against a ball of hardened steel at 1 Hz using different lubricants (regime of mixed friction). After 1000 cycles, the corresponding wear tracks were characterized by optical and scanning electron microscopy. High-resolution energy dispersive X-ray analyzes (EDX) allowed the visualization of chemical alterations within the wear tracks. For specific conditions, the nanostructures endured the tribological treatment. Our experiments provide a qualification of the tribological performance of the fs-LIPSS on TiN surfaces. T2 - E-MRS 2016 Spring Meeting, Symposium C: "Laser-material interactions for tailoring future applications" CY - Lille, France DA - 02.05.2016 KW - Femtosecond laser ablation KW - Laser-induced periodic surface structures (LIPSS) KW - Tribology KW - Friction KW - Wear KW - Titanium nitride PY - 2016 AN - OPUS4-36042 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Epperlein, Nadja A1 - Menzel, Friederike A1 - Schwibbert, Karin A1 - Koter, Robert A1 - Bonse, Jörn A1 - Sameith, Janin A1 - Krüger, Jörg A1 - Toepel, Jörg T1 - Influence of femtosecond laser produced nanostructures on biofilm growth on steel N2 - Large area periodic surface structures were generated on steel surfaces using 30-fs laser pulses at 790 nm wavelength. Two types of steel exhibiting a different corrosion resistance were used, i.e. a plain structural steel (corrodible) and a stainless steel (resistant to corrosion). Homogeneous fields of laser-induced periodic surface structures (LIPSS) were realized utilizing laser fluences close to the ablation threshold while scanning the sample under the focused laser beam in a multi-pulse regime. The nanostructures were characterized with optical and scanning electron microscopy. For each type of steel, more than ten dentical samples were laser-processed. These samples were subjected to microbial adhesion tests, investigating bacterial adhesion behavior on the laser structures in comparison to polished reference surfaces. Short term experiments (<24h) were carried out to determine initial biofilm development. E. coli as a typical bacterium representing pathogenic bacteria and Shewanella putrefaciens as metal corrosive bacterium were used for biofilm development analyses. Bacterial cell adhesion was determined microscopically after DAPI cell staining (DNA staining). Comparison of the coverage areas between nanostructured and polished surfaces revealed differences in cell adhesion behavior and biofilm structure. T2 - E-MRS 2016 Spring Meeting, Symposium C: "Laser-material interactions for tailoring future applications" CY - Lille, France DA - 02.05.2016 KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Biofilms KW - Steel PY - 2016 AN - OPUS4-36045 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Walter, Astrid A1 - von Oertzen, Alexander T1 - EU-Projekt HOMER, home made explosives (HMEs) and recipes characterisation N2 - Das EU-Projekt HOMER befasst sich mit den sogenannten Home Made Explosives (HMEs) und frei verfügbaren Rezepten für deren Herstellung. Diese Selbstlaborate spielen in der heutigen Zeit vor allem im Zusammenhang mit terroristischen Aktivitäten eine bedeutende Rolle. Informationen zu HMEs und ihrer Herstellung werden einfacher denn je über das Internet verbreitet. Hier knüpft das im 7. EU‑Forschungsrahmenprogramm finanzierte Projekt an und bezweckt, die im Internet verfügbaren Quellen auszuwerten und so die Informationslage für Sicherheitskräfte und Ermittlungsbehörden zu verbessern. Im Rahmen des Projektes wird eine automatisierte Suche von Rezepten im Internet entwickelt. Die gefundenen sowie die im Projekt generierten Informationen über HMEs sollen im Endergebnis in Form einer Software (Knowledge Management Platform) informationstechnisch nutzbar gemacht werden. Diese Datenbank soll auch für mobile Geräte zur Verfügung stehen. Der Schwerpunkt der Projektbeteiligung des Fachbereichs 2.3 Explosivstoffe der BAM liegt in der Bewertung der Rezepturen und der auf ihrer Grundlage hergestellten Laborate. Es wurden HMEs entsprechend der vorgefundenen Rezepte und unter Beachtung aller notwendigen Sicherheitsvorkehrungen hergestellt und anschließend sicherheitstechnisch geprüft und bewertet. Dabei wurden sowohl Handhabungsparameter wie die Empfindlichkeiten gegen Schlag, Reibung und thermische Einflüsse ermittelt, als auch die Leistungsparameter wie Detonationsgeschwindigkeit und Luftstoßdruckwirkung gemessen. Die gewonnen Erkenntnisse fließen in die genannte Datenbank ein und sollen beispielsweise Einsatzkräften vor Ort helfen, angemessene Schutzabstände zu ermitteln. Auch das Personal in Laboren der Kriminalämter profitiert von der zusammengetragenen Information über HMEs bei der Analyse von unbekannten Explosivstoffspuren. T2 - 14. BAM-PTB-Kolloquium zur chemischen und physikalischen Sicherheitstechnik CY - Berlin, Germany DA - 14.06.2016 KW - Homemade explosives KW - Explosivstoffe KW - TATP KW - Ammoniumnitrat PY - 2016 AN - OPUS4-36594 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Welter, T. A1 - Deubener, J. A1 - Reinsch, Stefan A1 - Marzok, Ulrich A1 - Müller, Ralf T1 - Glasstrukturen mit geringer Helium- und Wasserstoffpermeation N2 - Wasserstoffbarrieren aus Glas erfahren zunehmend Bedeutung als Werkstoff in der Energietechnik. Trotz wachsender Anwendungen liegen überwiegend empirisch gewonnene Beziehungen zwischen Glaszusammensetzung und Wasserstoffpermeation vor, die im wesentlichen aus dem Verhalten von Kieselglas abgeleitet werden. In dieser Studie werden daher topologische Parameter der Glasstruktur identifiziert und mit thermodynamischen Parametern korreliert. Auf der Seite der Glastopologie steht das freie Volumen und der Vernetzungsgrad des Netzwerkes während auf der thermodynamischen Seite die Konfigurationsentropie bzw. die Konfigurationswärmekapazität Aufschluss über die Verteilung des freien Volumens geben kann. Dabei wird angenommen, dass für Temperaturen weit unterhalb der Glasübergangstemperatur die chemische Löslichkeit von H2 zu vernachlässigen ist. Um die eingeschränkte Datenlage für die Wasserstoffpermeation kompositionell zu erweitern, wurden zusätzlich Heliumpermeationsmessungen ausgewertet. Die Ergebnisse zeigen, dass für Silicatgläser ein charkteristisches Verhältnis von freiem Volumen zu Netzwerkaufspaltung herrschen muss, um permeationsstabile Gläser zu erhalten. T2 - 90. Glastechnische Tagung CY - Goslar, Germany DA - 06.06.2016 KW - Glasstruktur KW - Helium- und Wasserstoffpermeation KW - Alkalialumosilicatsysteme KW - Thermodynamik KW - Energietechnik PY - 2016 AN - OPUS4-36583 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kulla, Hannes A1 - Rademann, K. A1 - Emmerling, Franziska T1 - In situ investigation of mechanochemical reactions with PXRD and Raman spectroscopy - cocrystals of pyrazinamide with dicarboxylic acids N2 - - Cocrystal formation of pyrazinamide with dicarboxylic acids proceeds either directly or via a crystalline intermediate. - Two new crystal structures were discovered by in situ investigations. T2 - ICS 2016 CY - Granada, Spain DA - 30.05.2016 KW - In situ KW - Mechanochemie KW - XRD KW - Cocrystal PY - 2016 AN - OPUS4-36620 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael A1 - Münster, Christoph A1 - Mente, Tobias A1 - Steger, Jörg A1 - Böllinghaus, Thomas T1 - Influence of experimental conditions and calculation method on hydrogen diffusion coefficient evaluation at elevated temperatures N2 - Hydrogen-assisted cracking (HAC) represents a significant failure risk for (high strength) creep resistant low-alloyed steel components in fossil-fired power plant applications at temperatures of up to and above 200 °C. This particularly applies to respective start-up and shut-down processes associated with alternating service-conditions in terms of load flexible power plants. For quantitative determination of localized crack critical hydrogen concentrations, the temperature dependent hydrogen diffusion coefficients have to be determined as exactly as possible. However, available literature provides a wide range of hydrogen diffusion coefficients for low alloyed steels with similar microstructures. Additionally, the available diffusion data seem not to be very reliable and their scatter increases with decreasing temperature. One reason is that the experimental boundary conditions can have a major impact on the determination of respective effective diffusion coefficients. Hence, the scope of this study is to evaluate the influence of the experimental boundary conditions on the derived diffusion coefficients. In addition, different methods for calculating diffusion coefficients are discussed. To elucidate such influences and to draw a line to practical application, the diffusion and trapping behavior in the creep resistant steel 7CrMoVTiB10 10 has been studied. For such purpose, hydrogen charged specimens were isothermally degassed at different temperatures using carrier gas hot extraction (CGHE). Based on experimental data, a numerical model has been developed by which the hydrogen transport behavior and the respective hydrogen distribution during CGHE can be assessed. It is demonstrated that the specimen heating rate has a large influence on the calculated diffusion coefficients under assumption of isothermal degassing which elsewhere has been underestimated in the assessment of diffusion data in creep-resistant steels. The numerical results suggest that calculation methods for diffusion coefficients are limited if compared to experimental results. It also turned out that the sample preparation time before CGHE can enormously influence determined diffusion coefficients. Consequently, non-homogeneous hydrogen concentration profiles have to be anticipated in the simulations to arrive at characteristic effusion curves consistent to respective CGHE experiments. In turn, validated diffusion coefficients are now available for the low-alloyed Cr-Mo-V steel which might be helpful to calculate appropriate hydrogen removal heat treatment procedures, for instance. T2 - International Hydrogen Conference - Material Performance in Hydrogen Environments CY - Jackson Lake Lodge, Moran, Wyoming, USA DA - 11.09.2016 KW - Hydrogen diffusion KW - Elevated temperatures KW - Welding KW - Creep-resistant steel KW - Numerical modeling KW - Calculation PY - 2016 AN - OPUS4-37403 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael A1 - Mente, Tobias A1 - Böllinghaus, Thomas T1 - Modeling of hydrogen-assisted cracking (HAC) in duplex stainless steels (DSS) N2 - Modeling of Hydrogen-Assisted Cracking (HAC) in Duplex Stainless Steels (DSS): - Hydrogen causes significant degradation in DSS and consequently HAC - Mechanisms of HAC have not been fully understood in two-phase microstructures - Mesoscale numerical modeling for HAC in DSS was created, coupled to the macroscale, enabling simulation of HAC in both phases independent from predefined crack paths T2 - International Hydrogen Conference - Material Performance in Hydrogen Environments CY - Jackson Lake Lodge, Moran, Wyoming, USA DA - 11.09.2016 KW - Hydrogen KW - Numerical modeling KW - Duplex stainless steel KW - Hydrogen assisted cracking PY - 2016 AN - OPUS4-37404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael A1 - Münster, Christoph A1 - Mente, Tobias A1 - Steger, Jörg A1 - Böllinghaus, Thomas T1 - Influence of Experimental Conditions and Calculation Method on Hydrogen Diffusion Coefficient Evaluation at Elevated Temperatures N2 - Hydrogen-assisted cracking (HAC) represents a significant failure risk for (high strength) creep resistant low-alloyed steel components in fossil-fired power plant applications at temperatures of up to and above 200 °C. This particularly applies to respective start-up and shut-down processes associated with alternating service-conditions in terms of load flexible power plants. For quantitative determination of localized crack critical hydrogen concentrations, the temperature dependent hydrogen diffusion coefficients have to be determined as exactly as possible. However, available literature provides a wide range of hydrogen diffusion coefficients for low alloyed steels with similar microstructures. Additionally, the available diffusion data seem not to be very reliable and their scatter increases with decreasing temperature. One reason is that the experimental boundary conditions can have a major impact on the determination of respective effective diffusion coefficients. Hence, the scope of this study is to evaluate the influence of the experimental boundary conditions on the derived diffusion coefficients. In addition, different methods for calculating diffusion coefficients are discussed. To elucidate such influences and to draw a line to practical application, the diffusion and trapping behavior in the creep resistant steel 7CrMoVTiB10 10 has been studied. For such purpose, hydrogen charged specimens were isothermally degassed at different temperatures using carrier gas hot extraction (CGHE). Based on experimental data, a numerical model has been developed by which the hydrogen transport behavior and the respective hydrogen distribution during CGHE can be assessed. It is demonstrated that the specimen heating rate has a large influence on the calculated diffusion coefficients under assumption of isothermal degassing which elsewhere has been underestimated in the assessment of diffusion data in creep-resistant steels. The numerical results suggest that calculation methods for diffusion coefficients are limited if compared to experimental results. It also turned out that the sample preparation time before CGHE can enormously influence determined diffusion coefficients. Consequently, non-homogeneous hydrogen concentration profiles have to be anticipated in the simulations to arrive at characteristic effusion curves consistent to respective CGHE experiments. In turn, validated diffusion coefficients are now available for the low-alloyed Cr-Mo-V steel, which can be helpful to calculate appropriate hydrogen removal heat treatment procedures. T2 - Project Meeting CAStLE CY - Colorado Springs, CO, USA DA - 07.09.2016 KW - Hydrogen KW - Diffusion Coefficient KW - Elevated Temperatures KW - Numerical Modeling KW - Carrier Gas Hot Extraction PY - 2016 AN - OPUS4-37408 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weltschev, Margit A1 - Schwarzer, Stefanie A1 - Eiben, Mario T1 - Comparison of the environmental stress cracking behaviour of polyethylene and polyethylene terephthalate as materials for dangerous goods packagings N2 - The chemical industry has expressed great interest in using polyethylene terephthalate (PET) as material for packagings for the transport of dangerous goods. Due to the high strength and stiffness of PET, the wall thickness and weight of packagings can be reduced. This is a relevant cost factor. PET is a semi-crystalline thermoplast which is produced by polycondensation of terephthalic acid and ethylene glycol. According to the European dangerous goods regulations RID and ADR, samples of PET design types of packagings for dangerous goods must be pre-stored with the original filling good for six months at 23°C, before the design type tests can be carried out. For packagings made of polyethylene (PE) tests to prove the stress cracking resistance by using laboratory methods are possible to reduce time and costs. Therefore, standard liquids, simulating the different types of damaging effects on PE are defined in RID and ADR. However, there is no information and research available about the damaging mechanisms on PET in comparison to PE, especially regarding to stress cracking resistance and test methods. The aim of this work is to compare the stress cracking resistance of PE and PET with the Full Notch Creep Test (FNCT), which was developed by chemical industry and is described in the standards EN ISO 16101 and EN 15507. It was investigated whether testing specimens made of PE and PET with a full coplanar notch around the middle of the specimens show weakening after the impact of a tensile force in a wetting solution (Lutensol® FSA 10) at 50°C in a test device on the basis of the FNCT. The test results confirmed the suitability of the method for eight PE grades. Unfortunately, this method couldn’t be used for PET because the specimens broke during notching. In addition the molding of the sheets and the following temper process for twelve hours are very time-consuming, and the specimens broke during notching due to the high brittleness of PET. Another possibility to provide evidence of stress cracking resistance of PE packagings is laid down in BAM’s Dangerous Goods Rule BAM-GGR 015. This test was carried out with PE and PET bottles to compare both materials. Therefore 1l test bottles were filled with a 5% wetting solution and mounted with a clamping tool for 28 days at 40°C. Tensile test specimens were cut out afterwards from the middle of the bottles in the deformed areas. Tensile strength and breaking elongation of PE specimens were determined in comparison to the PET specimens. The tensile properties of the PET specimens couldn’t be determined due to the strength and the stiffness of the material. In conclusion the only way to provide information about the stress cracking resistance of PET was to perform stacking tests. 1l bottles made of PE and PET were filled with a 5% wetting solution and stored with a stacking load for 28 days at 40°C according to EN ISO 16495. Design types of PE and PET both passed the stacking tests. T2 - EUROCORR 2016 CY - Montpellier, France DA - 11.09.2016 KW - polyethylene terephthalate KW - stress cracking resistance KW - test methods KW - dangerous goods packagings PY - 2016 AN - OPUS4-37448 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzweber, Markus A1 - Sobol, Oded A1 - Wirth, Thomas A1 - Böllinghaus, Thomas A1 - Unger, Wolfgang T1 - Deuterium permeation and cracking in duplex steels as viewed by ToF-SIMS and HR-SEM with data fusion N2 - Better understanding of hydrogen assisted degradation and trapping mecha-nisms requires sufficient imaging techniques for respective hydrogen-microstructure interaction studies, in particular with multi-phase metallic micro-structures [1]. The present work is focusing on the elucidation of deuterium be-havior in two austenitic-ferritic duplex stainless steels (DSS) under the assumption that deuterium behaves in many ways similarly to hydrogen [2]. For case studies standard 2205 and lean 2101 DSSs were chosen due to the extensive use of these steels in industry [3]. The analyses were conducted by using a novel in-situ permeation and Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) imaging technique or by ex-situ ToF-SIMS imaging following electrochemical charging experiments. Another pioneering procedure was data fusion (including chemometry) of results of powerful laterally resolved chemical analysis and high resolution structural characterization techniques . Results for the ex-situ observations showed a different influence of deuterium loading on the two steel grades as well as different damage mechanisms in each phase. Formation of sub-surface blisters between the ferrite and austenite were obtained in both the standard and the lean DSS. In both steels, an increased deuterium concentration was observed around deformed regions such as cracks, confirming that they originate from the presence of deuterium [4]. The formation of parallel cracks was obtained only in the austenite within the standard duplex whereas in the lean duplex the highest intensity of deuterium was obtained in the austenite along the ferrite-austenite interphase. In comparison, application of the novel in-situ permeation technique enabled to register and record the deuterium permeation through the material and the respective saturation sequence of the two phases as well as the interfaces. Faster diffusion of the deuterium was observed in the ferrite and a direct proof for deuterium enrichment at the austenite-ferrite interface has been given [1]. The integration of the specified techniques gives a better insight into the processes leading to hydrogen induced failure. These two experimental techniques provide very valuable tools for elucidation of respective metallurgical failure mechanisms that can be used for the validation of respective numerical models for hydrogen assisted cracking (HAC). T2 - 19. Arbeitstagung Angewandte Oberflächenanalytik CY - Soest, Germany DA - 05.09.2016 KW - ToF-SIMS KW - Hydrogen assisted cracking KW - Data fusion KW - SEM PY - 2016 AN - OPUS4-37484 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scheuerlein, A1 - Lackner, F. A1 - Savary, F. A1 - Rehmer, Birgit A1 - Finn, Monika A1 - Uhlemann, P. T1 - Mechanical properties of the HL-LHC 11 Tesla Nb3Sn magnet constituent materials N2 - A test campaign was launched to determine the mechanical properties of the HL-LHC 11 T Nb3Sn magnet components in order to accurately model the mechanical properties in Finite Element simulations that predict the stress and strain distribution in These magnets. Static and dynamic test methods have been applied for determining elastic materials behavior, and highly accurate Young’s moduli are obtained with the dynamic methods resonance and impulse excitation. These non-destructive methods also enable temperature dependent modulus measurements during in situ heat cycles. T2 - Applied Superconductivity Conference CY - Denver, Colorado, USA DA - 04.09.2016 KW - Young's modulus KW - Tensile test KW - Resonanz KW - Impact excitation PY - 2016 AN - OPUS4-37414 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babutzka, Martin A1 - Burkert, Andreas A1 - Heyn, A. T1 - Corrosion investigations by using gel-type electrolytes N2 - In the presentation different zinc coatings are presented and investigated. Their naturally formed protective layers are electrochemically characterized and corrosion relevant values are determined by using a gel pad based on polysaccharide. The corrosion relevant values allow the differentiation of various zinc coating systems and can describe the current protective effect provided by the coating. It is shown that gel-type electrolytes influence protective layers and coatings considerably less than corresponding bulk electrolytes. From the results it is evident that gel-type electrolytes represent a viable and promising field in corrosion research.zeige mehr T2 - EUROCORR European Corrosion Congress 2016 CY - Montpellier, France DA - 11.09.216 KW - Corrosion investigations KW - Gel-type electrolytes KW - Zinc coatings PY - 2016 AN - OPUS4-37496 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lüth, Peter A1 - Brandes, E. A1 - Frost, K. A1 - Kurth, Lutz A1 - Schmidt, Martin A1 - Michael-Schulz, Heike A1 - Uhlig, S. T1 - CEQAT-DGHS Ringversuchsprogramm der BAM in Kooperation mit QuoData und PTB N2 - Bei der Bewertung der Verlässlichkeit der im Labor gewonnenen Prüfergebnisse spielen Ringversuche eine entscheidende Rolle. Die Bundesanstalt für Materialforschung und -prüfung (BAM) unterstützt deshalb den weiteren Ausbau des Ringversuchsprogramms des im Jahr 2007 gegründeten Kompetenzzentrums zur Qualitätssicherung für Prüfungen von Gefahrgütern und Gefahrstoffen auf physikalische Gefahren (Centre for quality assurance for testing of dangerous goods and hazardous substances, CEQAT-DGHS). Bei allen bisher untersuchten Prüfmethoden besteht ein Verbesserungsbedarf. Die RV müssen daher zunächst auf die Methodenentwicklung, -verbesserung und -validierung abzielen und nicht auf Leistungstests. T2 - 14. Kolloquium zur chemischen und physikalischen Sicherheitstechnik (BAM-PTB-Kolloquium) CY - Berlin, Germany DA - 14.06.2016 KW - Gefahrgut KW - Gefahrstoff KW - Ringversuch KW - Prüfmethode KW - Validierung KW - Qualitätssicherung PY - 2016 AN - OPUS4-38465 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jürgens, Maria A1 - Olbricht, Jürgen A1 - Skrotzki, Birgit A1 - Fedelich, Bernard T1 - Ermüdungsverhalten, Lebensdauer und Schädigungsprozesse von P92 unter zyklischen Betriebsbedingungen N2 - Schnelle Lastwechsel mit hohen Temperaturgradienten führen zu thermischen und mechanischen Beanspruchungen v.a. in dickwandigen Bauteilen. Daraus ergibt sich ein komplexes Lastkollektiv, bei dem der Werkstoff sowohl durch Kriechermüdung als auch durch thermomechanische Ermüdung (TMF) geschädigt wird. Welche Auswirkungen hat eine gleichzeitige Änderung von Temperatur, mechanischer Beanspruchung und Arbeitsmedium auf die Schädigungsprozesse? T2 - KWT Dresden CY - Dresden, Germany DA - 18.10.2016 KW - LCF KW - P92 KW - TMF PY - 2016 AN - OPUS4-38587 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hemmleb, M. A1 - Bettge, Dirk A1 - Berger, D. A1 - Driehorst, I. T1 - 3D surface reconstruction with segmented BSE detector: New improvements and application for fracture analysis in SEM N2 - Application of 4Q-BSE detector and dedicated software enables 3D surface measurements of fracture samples in SEM. 3D surface measurement is independent from magnification and material invariant. Quantitative height measurements require careful detector adjustment and system calibration. Live 3D view allows a fast assessment of topographical features. In addition to SE and BSE imaging, 3D surface data help to analyse and interpret fracture samples. T2 - European Microscopy Congress 2016 CY - Lyon, France DA - 28.08.2016 KW - Topography KW - SEM KW - 3D analysis KW - Fractography PY - 2016 AN - OPUS4-38456 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sojref, Regine A1 - Nofz, Marianne A1 - Dörfel, Ilona A1 - Schulz, Wencke A1 - Wollschläger, Nicole A1 - Kranzmann, Axel T1 - Thin and porous sol-gel alumina coatings on a 9% Cr steel as a protection against high-temperature corrosion in power plants N2 - In order to reduce CO2 emissions fossil fuelled power stations with high combustion efficiency are being developed. The increase of the operating temperature, a common way to improve combustion efficiency, leads to enhanced corrosion of heat exchange steel tubes in the power plants. Within the framework of the European project “Production of Coatings for New Efficient and Clean Coal Power Plant Materials” (POEMA)", high temperature corrosion protection coatings are now under investigation. Thin porous sol-gel alumina films are promising candidate coating materials. Coatings were prepared by applying boehmite sols on grinded steel P92 and subsequent heat treatments at temperatures up to 650 °C. Thus a porous layer of worm-like particles was formed consisting of nano-crystallites and amorphous alumina. A dense interface with satisfying adhesion resulted from diffusion of chromium and iron ions out of the steel into the porous coating. However, the film locally exhibited some cracks caused by steep edges in the grinded steel surface. An appropriate substrate pretreatment should avoid this problem. The protection of the steel relies on the barrier function of the alumina coating and the formation of a dense chromia layer at the steel surface. T2 - ICC6 6th International Congress on Ceramics CY - Dresden, Germany DA - 21.08.2016 KW - High-temperature corrosion KW - Alumina KW - Chromium PY - 2016 AN - OPUS4-38354 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shashev, Yury A1 - Kupsch, Andreas A1 - Lange, A. A1 - Bruno, Giovanni A1 - Müller, Bernd R. A1 - Hentschel, M.P. A1 - Britzke, Ralf T1 - Optimizing visibility of phase gratings for Talbot-Lau X-ray imaging N2 - We investigated the efficiency of phase gratings, i.e., the visibility upon variation of different parameters. Rotating around an axis parallel to the grid lines of the phase grating changes the grating’s shape and thereby the initial distribution of phase shifts. This yields high visibilities for shorter propagation distances than derived from box shapes. Tilting the grating in the scattering plane allows continuous tuning of the grating’s height that corresponds to an ideal phase shift for a particular photon energy. This opens the way for tuning the design energy suitable for the material under investigation. Our study included simulations for monochromatic sources with the sampling procedure for rectangular and triangular phase gratings. T2 - HZB - 8th joint BER II and BESSY II User Meeting CY - Berlin, Germany DA - 07.12.16 KW - Phase grating KW - X-ray interferometry KW - X-ray imaging PY - 2016 AN - OPUS4-38823 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Becker, Ben T1 - Aging of composite pressure cylinder (COD-AGE) N2 - Subject, Aim and methods within the Project COD-AGE. Test methods and condition monitoring for Composite-cylinders T2 - Follow-up Workshop on statistical safety assessment CY - Berlin, Germany DA - 05.10.2016 KW - Aging KW - Composite cylinder KW - Non destructive testing PY - 2016 AN - OPUS4-39087 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Becker, Ben A1 - Munzke, Dorit A1 - Schukar, Marcus T1 - Zustandsüberwachung von Composite-Druckgefäßen mit faseroptischer Sensorik N2 - Einsatz der Faseroptik zur Zustandsüberwachung von Composite-Druckgefäßen. Aufbau, Integration, Messergebnisse. T2 - Follow-up Workshop on Statistical Safety Assessment of Composite Cylinders CY - Berlin, Germany DA - 05.10.2016 KW - Faseroptik KW - Zustandsüberwachung KW - Composite-Druckgefäße PY - 2016 AN - OPUS4-39088 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Laquai, René A1 - Müller, Bernd R. A1 - Kupsch, Andreas A1 - Nellesen, J. A1 - Tillmann, W. T1 - Characterizing damage evolution in metal matrix composites with X-ray refraction topography and in situ tensile loading N2 - In this study a metal-matrix-composite with aluminum matrix and Al2O3 particles was investigated with x-ray refraction topography and in-situ tensile loading. It could be observed that after reaching a certain load the specific surface increased steadily. However, the classical radiographs taken for comparison show no damage in the sample. T2 - 8th Joint BER II and BESSY II User Meeting CY - Berlin, Germany DA - 07.12.2016 KW - X-ray refraction KW - Metal matrix composites KW - In-situ loading KW - Synchrotron PY - 2016 AN - OPUS4-39113 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Bruno, Giovanni A1 - Müller, Bernd R. A1 - Hentschel, Manfred A1 - Britzke, Ralf T1 - Optimizing visibility of phase gratings for Talbot-Lau X-ray imaging N2 - We investigated the efficiency of phase gratings, i.e., the visibility upon variation of different parameters. Rotating around an axis parallel to the grid lines of the phase grating changes the grating’s shape and thereby the initial distribution of phase shifts. This yields high visibilities for shorter propagation distances than derived from box shapes. Tilting the grating in the scattering plane allows continuous tuning of the grating’s height that corresponds to an ideal phase shift for a particular photon energy. This opens the way for tuning the design energy suitable for the material under investigation. Our study included simulations for monochromatic sources with the sampling procedure for rectangular and triangular phase gratings. T2 - User-Meeting CY - Berlin, Germany DA - 8.12.2016 KW - Talbot-Lau interferomerty KW - Phase grating KW - Synchrotron radiation PY - 2016 AN - OPUS4-39096 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Munzke, Dorit A1 - Becker, Ben A1 - Schukar, Macus T1 - Zustandsüberwachung von Composite-Druckgefäßen mit faseroptischer Sensorik N2 - Funktionsweise, Integration und Messergebnisse von opt. Fasern zur Zustandsüberwachung von Composite-Druckgefäßen. T2 - 3. Workshop Themenfeld Material CY - Berlin, Germany DA - 12.10.2016 KW - Faseroptik KW - Zustandsüberwachung KW - Composite-Druckgefäße PY - 2016 AN - OPUS4-39097 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Armatys, Kamila A1 - Adamczyk, Burkart A1 - Adam, Christian A1 - Galetz, M.C. A1 - Pflumm, R. T1 - Corrosion and abrasion resistant protective coatings for biomass combustion N2 - One of the alternative renewable fuels is biomass but it is a difficult fuel because of its diversity and complexity. It can contain high percentages of K and Cl responsible for corrosion together with sand that have additionally an abrasive effect during combustion. Because of permanently extending the surface reaction due to abrasion the corrosion of the materials increases. In particular in power plants, the superheater tubes are exposed to a corrosive abrasive attack that is one of the main sources of concern. The development of new alloys for multilayer surface, which combines corrosive and abrasive resistance is therefore of high importance. Those new technical approaches must be at the same time cost-effective to be an alternative to conventional materials. The aim of the presented investigation methods is to test and develop suitable alloys for coatings for the super heater tubes of biomass power plants. First results of abrasion investigations show improved abrasion resistance compared to the multi-component reference material Alloy 625. T2 - Young Researchers Conference: Energy Efficiency & Biomass CY - Wels, Austria DA - 24.02.2016 KW - Coatings KW - Corrosion PY - 2016 AN - OPUS4-35713 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Harald Rune A1 - Hoffmann, Katrin A1 - Schwibbert, Karin A1 - Sameith, Janin A1 - Toepel, Jörg A1 - Resch-Genger, Ute T1 - Imaging of local pH in biofilm using polymeric sensors: towards the elucidation of microbial induced corrosion N2 - Microbial induced corrosion (MIC) is a crucial problem in many technical plants as well as fuel tanks, leading to considerable damage and huge financial losses. Successful prevention of MIC requires the localization of first signs of corrosion as well as the identification of factors influencing the corrosion process. In this respect, also the determination of corrosion rates can be of interest for the possible prevention of MIC. Hence, there is a growing need for sensitive and preferably inexpensive tools that enable the early detection of MIC. Of special interest are methods, which provide spatially and time-resolved information and allow the study of changes on metal surfaces as prerequisites for a more detailed analysis of ongoing corrosion processes at a MIC-affected site. Biofilm formation can lead to changes in pH, oxygen and chloride concentration as well as to the release of certain metal ions like Fe(II) and Mn(II) depending on the type of metal surface involved. Hence, optical methods enabling the detection of these analytes at very low concentration and monitoring of their changes can be used for MIC detection. Here, we propose to utilize polymeric nanosensors for MIC detection via the determination of the local pH value changes in different biofilms. Such nanosensors are known to have several advantages in imaging applications such as intracellular pH measurements including the ease of doping or labeling with a multitude of analyte-responsive and inert dye molecules for the realization of a high analyte sensitivity and ratiometric sensing. Moreover, they can be surface functionalized with target-specific ligands e.g., lectins, for the specific binding to the outer surface of certain types of bacteria. In this respect, different polymer architectures will be studied to identify an optimal candidate in terms of imaging performance in conjunction with several classes of pH-responsive fluorescent dyes like cyanines, aza-BODIPYs, and xanthenes, utilizing different mechanism of signal generation such as photo-induced electron transfer or protonation-induced changes in the spectral position of absorption and emission spectra. T2 - Europtrode CY - Graz, Austria DA - 20.03.2016 KW - Nanosensor KW - Microbial induced corrosion KW - Imaging KW - Nanosensor KW - Mikrobiell induzierte Korrosion KW - Bildgebung PY - 2016 AN - OPUS4-35628 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Steinborn, Gabriele A1 - Woydt, Mathias A1 - Gemeinert, Marion T1 - Stable aqeous niobium carbide suspensions for production of homogeneous hard materials N2 - Hard materials consist of a hard phase embedded in a metallic binder. In order to achieve high toughness and strength, it is necessary to have a perfect mixing of hard phase and binder, which is mainly achieved by ball milling. Niobium carbide (NbC) has a high potential to substitute tungsten carbide as hard material. The publication presents the development of stable homogeneous and de-agglomerated NbC-dispersions. To prevent agglomeration of the powder, stable suspensions were achieved by surface treatments with the dispersants (PD and HD), which resulted in a charge reversal from a negative to a positive zeta potential. This surface-modified powder guaranteed a stable re-dispersion in the binder suspension. Nickel powder was added as metallic binder. This suspension was suited for 3D-printing. The green samples could be sintered in vacuum or Argon atmosphere. T2 - 91. Jahrestagung der deutschen keramischen Gesellschaft CY - Freiberg, Germany DA - 07.03.2016 KW - Niobium carbide powder KW - Stable suspensions KW - Reduction of agglomerates PY - 2016 AN - OPUS4-35636 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Taabache, Soraya A1 - Bertin, Annabelle A1 - Maskos, M. T1 - Microfluidic-Assisted Self-Assembly of Dendritic Amphiphiles N2 - The controlled production of supramolecular aggregates formed by the self-assembly of dendritic amphiphiles is of great interest owing to their potential application in the fields of nanotechnology and nanomedicine. Dendritic amphiphiles as building blocks offer the advantage that their structure and size can be precisely tuned through organic synthesis. This synthetic flexibility enables the fine-tuning of the hydrophobic to hydrophilic ratio of the dendritic segments, which mainly controls the morphology of the self-assembled structures. A promising method for the controlled preparation of supramolecular assemblies is based on the use of micromixers.[5,6] Due to their mixing times in the range of milliseconds at the microscale level, the application of such microfluidic systems benefits from a high mixing efficiency, a low mixing time and a reproducible synthesis compared to conventional batch-based techniques such as the solvent injection method or the film hydration method. Herein, we report on the microfluidic-assisted self-assembly of several dendritic amphiphiles and the impact of the mixing parameters on the self-assembly process. T2 - Makromolekulares Kolloquium 2016 CY - Freiburg im Breisgau, Germany DA - 24.02.2016 KW - Dendritic amphiphiles KW - Self-assembly KW - Dendrimersomes KW - Micromixer KW - Microfluidic PY - 2016 AN - OPUS4-35477 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Oesch, Tyler T1 - In-situ CT investigation of pull-out failure for reinforcing bars embedded in conventional and high-performance concretes N2 - The use of high-performance concretes holds great promise for many structural applications. This paper investigates the performance of these materials when used in combination with traditional reinforcing bars. An improved understanding of failure during reinforcing bar pull-out from high-performance concretes is needed in order to better predict the embedment length required to develop full reinforcing bar pull-out strength and the required thickness of reinforcing bar cover for adequate corrosion protection. The cracking structures surrounding the reinforcing bars were analyzed using x-ray computed tomography (CT) in order to determine the stress states causing failure. This was accomplished by conducting in-situ reinforcing bar pull-out experiments during CT scanning. A conventional concrete, a high-strength concrete, and a high-strength fiber reinforced concrete were all tested during the experiments. The results of these experiments showed that the levels of brittleness of the different concrete materials had a major impact on the failure mechanisms that they experienced during reinforcing bar pull-out. It was also clear that the specimen geometry and the casting method had a major impact on fiber orientation. The inclusion of fibers within concrete was also found to significantly improve strength and corrosion protection during reinforcing bar pull-out. T2 - 6th Conference on Industrial Computed Tomography CY - Wels, Austria DA - 09.02.2016 KW - Fiber KW - Reinforcing Bar KW - Computed Tomography KW - In-Situ KW - High-Performance Concrete PY - 2016 AN - OPUS4-35521 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lauer, Franziska A1 - Kneipp, Janina A1 - Weidner, Steffen A1 - Seifert, Stephan T1 - Multivariate statistics applied to MALDI-TOF MS data of pollen samples N2 - Current pollen screening information networks are based on time-consuming, microscopic determination of the genus-specific pollen morphology. Additionally, the given information relies on prediction of plant growth, wind direction and seasonal information. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was introduced for rapid analysis of complex biological samples. MALDI-TOF provides the possibility to measure species-specific mass peak patterns of pollen and offers a powerful tool for investigation of taxonomic relations. Our objective is to develop a fast, reliable, routine method for detecting single pollen grains in pollen mixtures. The obtained spectra are analyzed by multivariate statistics. T2 - 49. Jahrestagung der Deutschen Gesellschaft für Massenspektrometrie CY - Hamburg DA - 28.02.2016 KW - Pollen KW - Datenanalyse KW - Hauptkomponentenanalyse PY - 2016 AN - OPUS4-35523 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fischer, Franziska A1 - Joester, Maike A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Survival of the fittest - Competetive cocrystal reactions in the ball mill N2 - Mechanochemistry is increasingly used for synthesizing various materials including cocrystals and metal organic compounds. Although this synthesis approach offers a fast and pure synthesis in high yields there is a lack in understanding the mechanisms of milling reactions. The driving forces triggering the formation of cocrystals under milling conditions were investigated using a set of multi-component competitive milling reactions. In these reactions, different active pharmaceutical ingredients were ground together with a further compound acting as coformer. The study was based on new cocrystals including the coformer anthranilic acid. The results of the competitive milling reactions indicate that the formation of cocrystals driven by intermolecular recognition are influenced and inhibited by kinetic aspects including the formation of intermediates and the stability of the reactants. T2 - Berliner Chemie Symposium CY - Berlin, Germany DA - 12.04.2016 KW - milling KW - cocrystal KW - mechanochemistry PY - 2016 AN - OPUS4-35862 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Greiser, Sebastian A1 - Sturm, Patrick A1 - Gluth, Gregor A1 - Hunger, M. A1 - Jäger, Christian T1 - 29Si-27Al NMR to verify and distinguish Qn(mAl) sites in zeolites and geopolymers N2 - One-part-geopolymers, produced by addition of water to a mixture of solid silica and sodium alumi-nate, are a less exhaustively studied approach to form geopolymeric binders. Depending on the silica source, the reaction products show significant amounts of zeolite Na-A besides amorphous compounds. Previously, 29Si MAS NMR has been used to analyze the chemical structure of such one-part geopolymers, having crystalline structures and amorphous phases (Q2, Q3, Q4). In this work, pure zeolites and three different one-part-geopolymers cured for 1 day were investigated by 29Si-27Al TRAPDOR NMR. It was used to identify aluminum phases in overlapping silicon sites. Zeolites Na-X (Si/Al=1.4) and Na-Y (Si/Al=2.7) served as model systems to measure the TRAPDOR effect of the structural units Q4(mAl). Both materials show several Q4(mAl) signals, which are all separated by their chemical shifts. The more aluminum surrounds the silicon tetrahedron the higher are the normalized TRAPDOR difference signals (S0/∆S). The intensity ratios between Q4(mAl) to Q4({m-1}Al) of these signals is fixed but vary slightly between both zeolites. These results are transferred to the complex geopolymer structure. T2 - 57th Experimental nuclear magnetic resonance conference CY - Pittsburgh, PA, USA DA - 10.04.2016 KW - NMR KW - 29Si-27Al TRAPDOR MAS KW - Geopolymer KW - One-part formulation KW - Rice husk ash PY - 2016 AN - OPUS4-35864 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nguyen, Thi Yen A1 - Bernardes, C. A1 - Minas da Piedade, M. E. A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Direct evidence of polyamorphism in paracetamol N2 - While polymorphism is a common phenomenon in the crystallization processes of organic compounds, polyamorphism has gained importance only recently. Using sophisticated sample environments and applying in situ scattering methods and vibrational spectroscopy, the complete crystallization process of organic compounds from solution can be traced and characterized. Diffuse scattering from amorphous intermediates can be investigated by analyzing the atomic pair Distribution function (PDF) to gain further insights into molecular pre-orientation. The crystallization behavior of Paracetamol was studied exemplarily under defined, surface-free conditions. Based on the choice of the solvent, the formation of different polymorphs is promoted. The thermodynamically stable form I and the metastable orthorhombic form II could be isolated in pure form directly from solution. For both polymorphs, the crystallization from solution proceeds via a distinct amorphous precursor phase. PDF analyses of these different amorphous states indicate a specific pre-orientation of the analyte molecules introduced by the solvent. The resulting crystalline polymorph is already imprinted in these proto-crystalline precursors. Direct experimental evidence for the polyamorphism of paracetamol is provided. T2 - Annual CM1402 crystallize COST meeting CY - Coimbra, Portugal DA - 06.04.2016 KW - Paracetamol KW - Crystallization KW - In situ analysis KW - Active pharmaceutical ingredient (API) PY - 2016 AN - OPUS4-35873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wallau, Wilma A1 - Pirskawetz, Stephan A1 - Meng, Birgit T1 - Alkali-Kieselsäure-Reaktion in Beton - Entwicklung eines Prognoseverfahrens N2 - Zur Vermeidung der schädigenden Alkali-Kieselsäure-Reaktion in Betonbauwerken wird die Alkalireaktivität von Gesteinskörnungen im Vorhinein getestet. Der 60°C-Betonversuch ermöglicht eine vergleichsweise schnelle Einschätzung nach fünf-monatiger Testzeit. Dazu wird die Dehnung von Betonprüfkörpern, die mit der zu testenden Gesteinskörnung hergestellt wurden, manuell alle 28 Tage gemessen. Ein alternatives, an der BAM in den vergangen Jahren entwickeltes Verfahren setzt Dehnungssensoren ein, um kontinuierlich und online zu messen. Die Dehnungskurven sind eine gute Grundlage sowohl für die Prognose vom Expansionsverhalten während des Tests als auch für die Validierung von Expansionsmodellen. T2 - 3. Workshop im Themenfeld Material zu den Schwerpunktthemen "Laufende Projekte und neue Aktivitäten" CY - Berlin, Germany DA - 12.10.2016 KW - Baustoffe KW - Alkali-Kieselsäure-Reaktion PY - 2016 AN - OPUS4-40156 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rosemann, Paul A1 - Baumann, O. A1 - Müller, C. A1 - Gottwald, W.-R. A1 - Modersohn, W. T1 - Einfluss der Oberflächennachbearbeitung auf die Korrosionsbeständigkeit von Schweiß-nähten des Duplexstahls 1.4062 N2 - Die Korrosionsbeständigkeit geschweißter Konstruktionen aus nichtrostenden Duplexstählen wird von den Schweißparametern und der Nachbehandlung der Oberflächen bestimmt. Eine etablierte Methode der Schweißnahtnachbehandlung ist das Strahlen der Oberfläche mit Glasperlen. Diese Methode soll aus wirtschaftlichen Gründen durch das Strahlen mit Korund ersetzt werden, welches deutliche Zeit- und Kostenvorteile bietet. Besonders bei der Lochkorrosionsbeständigkeit hat sich das Schleifen mit Korund bereits als nachteilig erwiesen, weshalb diese Umstellung auch beim Stahlen kritisch hinterfragt wird. Daher wurden Probeschweißungen bei der Firma Modersohn hergestellt und mit verschiedenen Oberflächenbearbeitungsmethoden (Glasperlenstrahlen, Korundstrahlen, Beizen, Elektropolieren, Schleifen) nachbehandelt. Diese verschiedenen Oberflächenzustände wurden analytisch (REM, Rauheit) charakterisiert und hinsichtlich ihrer Lochkorrosionsbeständigkeit vergleichend untersucht werden, um die Eignung des Strahlens mit Korund zu beurteilen. T2 - GfKORR-Jahrestagung 'Duplex-Stähle – Nische oder Zukunft ?' CY - Frankfurt/M., Germany DA - 15.11.2016 KW - Korrosionsbeständigkeit KW - Schweißnähte KW - Duplexstahl PY - 2016 AN - OPUS4-39470 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rosemann, Paul A1 - Kauss, Norman A1 - Heyn, A. T1 - Einfluss des Schwefelgehalts auf die Korrosionsbeständigkeit des nichtrostenden Stahls 1.4404 N2 - Die Korrosionsbeständigkeit nichtrostender Stähle wird maßgeblich von ihrer chemischen Zusammensetzung bestimmt. Der tendenzielle Einfluss ist für die Hauptlegierungselemente in der wissenschaftlichen Fachliteratur beschrieben. Bei Begleitelement Schwefel gibt es dagegen keine konkreten Untersuchungen die belegen, ab welchem Gehalt mit einer Verringerung der Korrosionsbeständigkeit zu rechnen ist. Im Lichtbogenschmelzofen wurden verschiedene Legierungen mit abgestuftem Schwefelgehalten hergestellt, um den Einfluss dieses Begleitelementes auf die Korrosionsbeständigkeit systematisch zu untersuchen. Die KorroPad-Prüfung und die Bestimmung kritischer Lochkorrosionspotentiale wurden zur Charakterisierung der Legierungen genutzt. Beide Methoden belegen eine zunehmende Verringerung der Lochkorrosionsbeständigkeit mit dem Schwefelgehalt. T2 - GfKORR-Jahrestagung 'Duplex-Stähle – Nische oder Zukunft ? CY - Frankfurt/M., Germany DA - 15.11.2016 KW - Schwefelgehalt KW - Korrosionsbeständigkeit KW - Nichtrostender Stahl PY - 2016 AN - OPUS4-39472 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, C. A1 - Rosemann, Paul A1 - Diehl, V. A1 - Halle, T. T1 - Einfluss der Abkühlgeschwindigkeit auf die Korrosionsbeständigkeit martensitischer nichtrostender Stähle N2 - Martensitische nichtrostende Stähle werden in verschiedenen technischen Bereichen eingesetzt, bei denen eine optimale Kombination aus hoher mechanischer Festigkeit und guter korrosiver Beständigkeit gefordert wird. Beide Eigenschaften werden in der Industrie primär durch die Wärmebehandlung gesteuert. Die Korrosionseigenschaften sind dabei stark von der diffusionsbedingten Bildung und Auflösung von Chromkarbiden abhängig. In vergangenen wissenschaftlichen Arbeiten konnte nachgewiesen werden, dass die Abkühlgeschwindigkeit nach dem Austenitisieren einen großen Einfluss auf die Bildung solcher Karbide hat. Der Einfluss der Abkühlgeschwindigkeit auf die Lochkorrosionsbeständigkeit wurde an den Stählen 1.4108 und 1.4116 systematisch untersucht. Mit Hilfe des Stirnabschreckversuches wurde dabei die Abkühlgeschwindigkeiten variiert und anschließend die Veränderung von Gefüge, Lochkorrosionsbeständigkeit und Härte untersucht. Als Ergebnis konnten kritische Abkühlgeschwindigkeiten ermittelt werden, bei denen eine kritische Verringerung der Korrosionsbeständigkeit einsetzt. T2 - GfKORR-Jahrestagung 'Duplex-Stähle – Nische oder Zukunft ?' CY - Frankfurt/M., Germany DA - 15.11.2016 KW - Korrosionsbeständigkeit KW - Martensitische nichtrostende Stähle KW - Abkühlgeschwindigkeit PY - 2016 AN - OPUS4-39473 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -