TY - JOUR A1 - Schmidt, Wolfram A1 - Mota, Berta A1 - Ramirez Caro, Alejandra T1 - Einfluss der gesteinskörnung auf die Rheologie von Beton N2 - Die meisten Einflüsse auf die Rheologie von Beton wirken auf sehr kleinen Skalenebenen. Einflussgrößen im Millimeter oder Zentimeterbereich sind im Wesentlichen auf den Sand und die Gesteinskörnung beschränkt. Letztere machen aber in den meisten Betonen 50 %-70 % des Gesamtvolumens aus, was bei Untersuchungen zur Steuerung der Verarbeitungseigenschaften von Beton häufig vernachlässigt wird. Während Betonzusatzmittel und Zusatzstoffe bei geeigneter Wahl die Rheologie sehr gezielt beeinflussen können, eignen sich Sand und Gesteinskörnung weniger gut zur Steuerung der Rheologie, aber sie tragen zur Rheologie des Gesamtsystems bei. Hierbei können Effekte aus Sand und Gesteinskörnung die Effekte von Zusatzmitteln und Zusatzstoffen überlagern und im ungünstigsten Falle sogar nahezu unwirksam machen. Deshalb sollten Ergebnisse zur Verarbeitbarkeit von Bindemittelsystemen nur mit großer Sorgfalt auf Beton übertragen werden. Es ist wichtig, den Einfluss des Sandes und der Gesteinskörnung besser zu verstehen, um diese so abzustimmen, dass sie Effekte aus Fließmitteln positiv ergänzen anstatt diesen entgegenzuwirken. Durch eine gezielte Abstimmung lassen sich Kosten wirksam sparen. KW - Gesteinskörnung KW - Rheologie KW - Fließgrenze KW - Viskosität KW - Beton PY - 2018 VL - 3 SP - 42 EP - 51 PB - ad-media GmbH CY - Köln AN - OPUS4-47044 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Schmidt, Wolfram A1 - Leinitz, Sarah A1 - Mota, Berta A1 - Crasselt, Claudia ED - Liu, Jiaping ED - Wang, Ziming ED - Holland, Terence ED - Huang, Jing ED - Plank, Johann T1 - Influence of the aqueous phase of cement paste on the rheology in the presence of PCE N2 - The paper presents rheometric results and hydration curves for cementitious systems based on cement mixed with different aqueous phases at solid volume fraction of  = 0.45. The varied aqueous phases were deionized water, limewater, the filter residue of a cement paste mixed at w/c = 2.0, and the filtrate of cement paste at solid volume fraction of 0.45. Each cementitious system provided different amounts and sizes of particles formed in the aqueous phase. The pastes were observed with and without polycarboxylate ether based superplasticizer. It was observed that the presence of particles causes higher PCE saturation dosages to achieve a minimum value, but the minimum value is only affected in the case of large particles. In all cases with and without PCE, the presence of small particles causes increased plastic viscosity. In addition, with decreased number and size of hydrates in the aqueous phase the hydration was retarded, which was specifically pronounced in the presence of PCE KW - Aqueous phase of cement paste KW - Polycarboxylate ether KW - Rheology KW - Yield stress KW - Plastic viscosity KW - Heat of hydration KW - Syngenite KW - Solid volume fraction PY - 2018 SN - 978-1-64195-029-9 SP - SP-329-34, 428 EP - 443 PB - American Concrete Institute CY - Farmington Hill, Michigan AN - OPUS4-47107 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shamsuddoha, Md A1 - Hüsken, Götz A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Baeßler, Matthias T1 - Ternary mix design of grout material for structural repair using statistical tools N2 - Repair is an indispensable part of the maintenance of structures over their lifetimes. Structural grouting is a widely used remediation technique for concrete components, trenches, mine subsidence, dam joints, restoration of masonry structures, and geological stabilizations. A structural grout system should be injectable in narrow spaces and hence include ingredients with finer particles. Ultrafine cements are ideal for these type of demanding grouts due to their superior properties compared to that of the less expensive, but coarser ordinary Portland cement (OPC). Supplementary cementitious materials (SCMs) are often used to replace OPC clinker based binder in order to modify certain properties and to reduce costs. The most commonly used SCMs are fly ash (FA), and ground granulated blast furnace slag (GGBS). For various special applications microsilica (MS), and metakaolin (MK) are also used. Identifying the optimum replacement contents of OPC by SCMs are a challenge during the design of such grouts. The aim of this experimental study is to investigate the effect of the selected SCMs (FA, MS and MK) on the slump flow, time of efflux, viscosity, shrinkage, and compressive and flexural strength of ultrafine cement based grouts with constant water-binder ratio and superplasticizer content. The test program was formulated using Box-Behnken design principles. Maximum percentages of replacement with ultrafine cement was 6% by volume of cement for MS and 16% for FA, and MK. The results suggest that most investigated grouts have the potential to be used for structural applications. The appropriate quadratic models are then formulated through statistical tools and presented as response surfaces. The trends indicate that fly ash improves the rheological properties, whereas microsilica and metakaolin positively affect shrinkage and mechanical properties to some extent. Based on the influence of SCMs and priorities among the properties, Decision Matrix Analysis (DMA) is carried out to select the most suitable ones among the SCMs. The analysis suggests that microsilica and fly ash are more suitable as SCMs than metakaolin without affecting the properties. KW - Grouting KW - Microsilica KW - Fly ash KW - Metakaolin KW - Workability KW - Viscosity KW - Strength KW - Mix design KW - Box-Behnken KW - Decision matrix analysis PY - 2018 DO - https://doi.org/10.1016/j.conbuildmat.2018.08.156 SN - 0950-0618 SN - 1879-0526 VL - 189 SP - 170 EP - 180 PB - Elsevier Ltd. AN - OPUS4-45922 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Crasselt, Claudia A1 - Schmidt, Wolfram A1 - Sturm, Heinz T1 - Influence of Rheology Modifying Admixtures on Hydration of Cementitious Suspensions N2 - The presence of polycarboxylate ether (PCE) based superplasticizers (SPs) has an enormous influence on the early hydration of cement. The hydration is retarded and the timing of formation and the morphology of hydrates is affected. This short paper presents experimental results about the influence of delayed addition time of PCE SPs on hydration of cement and alite pastes, investigated by isothermal heat flow calorimetry. For cement as well as for alite pastes the hydration is retarded with SP, whereby the high charge PCE has a stronger retarding effect than the low charge PCE. The retardation caused by PCE is much more pronounced for alite than for cement mixes. If PCE is added later to the mix, the induction period is shortened and the hydration is accelerated compared to simultaneous addition. This applies for cement and alite pastes. With delayed PCE addition the alite shows a clearly less retarded setting and main hydration than after simultaneous addition. It is obvious that for alite pastes there is less retardation the later the addition of SP. T2 - 6th International Symposium on Nanotechnology in Construction CY - Hong Kong, China DA - 02.12.2018 KW - Polycarboxylate ether (PCE) KW - Early hydration KW - Cement PY - 2018 SP - 1 EP - 8 AN - OPUS4-47204 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Schmidt, Wolfram A1 - Ramirez Caro, Alejandra A1 - Sojref, Regine A1 - Mota Gassó, Berta ED - Greim, M. ED - Kusterle, W. ED - Teubert, O. T1 - Contribution of the coarse aggregates to rheology - effects of flow coefficient, particle size distribution, and volume fraction N2 - In order to observe the effect of the aggregate phases between 2 mm and 16 mm without overlap with rheological effects induced by the cement hy-dration and without interactions with a threshold fine sand particle size that affects both, paste and aggregates, rheological experiments were conducted on a limestone filler based paste mixed with aggregates up to 16 mm. Vari-ous aggregate fractions were blended and mixed with the replacement paste in different volumetric ratios. The dry aggregates’ flow coefficients were determined and compared to yield stress and plastic viscosity values at different aggregate volume fractions. The results indicated that the flow coefficient is not a suitable parameter to predict the performance of the aggregates in the paste. It was shown that the yield stress of pastes is largely determined by the blend of different aggregate fractions, while the plastic viscosity to large extend depends upon the coars-est aggregate fraction. Based on the results, ideal aggregate composition ranges for minimised yield stress are presented. For the plastic viscosity no such grading curves to achieve minimum values could be found, but high viscosity curves are identified. KW - Rheology KW - Flow Coefficient KW - Particle Size Distribution KW - Volume Fraction KW - Cement KW - Concrete KW - Reference Material KW - Limestone Filler PY - 2018 SN - 978-3-7469-1878-5 SP - 96 EP - 108 PB - tredition GmbH CY - Hamburg AN - OPUS4-44434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Leinitz, Sarah A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten T1 - Assessment of rheological effects in the binder on the rheology of mortar and concrete N2 - In the last years flowable concrete has become increasingly important in applications such as, for systems with highly reinforced concrete with a complicated formwork, or sprayed concrete and 3D-printing of concrete. For all these applications it is necessary to have tailored rheological properties. Rheology can be described by values of yield stress and plastic viscosity, which can be determined for example by evaluation of rheometer measurements. But for different materials various rheometers with different geometries and stirrers are being used. To see the effects from paste in concrete, it is necessary to investigate mixes of paste, mortar and concrete, stepwise. But currently there exists no device, which is calibrated for these different systems at once. Due to this fact, conventional tests such as V-funnel efflux-time and flow diameter were determined, as well as rheometer data in different cell sizes and geometries. In this study the assessment of rheological effects in the binder on the rheology of mortar and concrete was investigated by using combination of two rheometers. T2 - Rheologische Messungen an Baustoffen 2018, 27. Workshop und Kolloquium CY - Regensburg, Germany DA - 07.03.2018 KW - Rheology KW - Cement KW - Mortar KW - Upscaling KW - Superplasticizer PY - 2018 SN - 978-3-7469-1878-5 VL - 27 SP - 109 EP - 111 PB - tredition GmbH AN - OPUS4-44444 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Piechotta, Christian A1 - Iznaguen, Hassan A1 - Traub, Heike A1 - Feldmann, Ines A1 - Köppen, Robert A1 - Witt, Angelika A1 - Jung, Christian A1 - Becker, Roland A1 - Oleszak, Katrin A1 - Bücker, Michael A1 - Urban, Klaus A1 - Reger, Christian A1 - Ostermann, Markus T1 - Bewitterungsszenarien im Vergleich – Veränderungen in der Oberflächenmorphologie von Polypropylen (PP) und Polystyrol (PS) unter dem Aspekt des Austrags von polybromierten Flammschutzmitteln N2 - Gegenstand der vorzustellenden Arbeiten ist die Prüfung der Umwelt-beständigkeit und -verträglichkeit von Materialien und Produkten hinsichtlich der Emission von potenziellen Schadstoffen in die Umwelt. Hierzu werden chemisch-physikalische Einflüsse (Bewitterung) und mikrobielle Beanspruchungen an Modellmaterialien evaluiert. So werden die Freisetzungsraten von Schadstoffen in Abhängigkeit der Beanspruchung beschrieben. Als Modellmaterialien kommen die Polymere Polystyrol (PS) und Polypropylen (PP) zum Einsatz. Synergistische Effekte der Bewitterungsparameter und der mikrobiologischen Beanspruchung sollen dabei ebenso betrachtet werden, wie die gezielte Alterung. Auch findet eine Beschreibung des Verhaltens der ausgetragenen Schadstoffe in den Umweltkompartimenten Boden oder Wasser statt. Hier sind mit Hilfe der zu entwickelnden Screening- und non-Target-Analyseverfahren die Transformation und der Metabolismus durch Mikroorganismen zu beschreiben. Aus den Ergebnissen sollen Korrelationen zwischen den künstlichen Alterungsverfahren und realen Szenarien abgeleitet werden. T2 - 47. Jahrestagung der GUS CY - Blankenloch-Stutensee, Germany DA - 21.03.2018 KW - Schadstoffaustrag KW - Umweltsimulation KW - Bewitterung PY - 2018 SN - 978-981-18507-2-7 VL - 47 SP - 115 EP - 128 AN - OPUS4-49802 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Le, Quynh Hoa T1 - Electrochemical study on wellbore constellations for CO2 injection N2 - Carbon Capture and Storage (CCS) is identified as an excellent technology to reach the target of CO2 reduction. However, the safety issue and cost effectiveness hinder the future of CCS. For the reliability and safety issues of injection wells the corrosion resistance of the materials used needs to be determined. In this study, representative low cost materials including carbon steel 1.8977 and low alloyed steel 1.7225 were embedded in cement to mimic the realistic casing-cement interface. Electrochemical studies were carried out using these metal-cement specimens in comparison with those made of metal only in CO2 saturated synthetic aquifer fluid, at 333 K, to reveal the effect of cement on the steel performance. The results showed the protective effect of cement on the performance of pipeline metals during polarisation process. However, the corrosion current density was high in all cases, with and without cement, indicating that the corrosion resistance of these materials is low. This conclusion was supported by the surface analysis of the polarized specimens, which revealed both homogenous and pitting corrosions. Furthermore, to reveal the possible protective performance of FeCO3, the pipeline steels were pre-carbonated and then tested in the same condition as freshly polished specimens. T2 - EUROCORR 2018 CY - Krakow, Poland DA - 09.09.2018 KW - CCUS KW - Supercritical/dense phase CO2 KW - Carbon steels KW - Martensitic steel KW - Superaustenite steel KW - Injection KW - Impurities PY - 2018 AN - OPUS4-46279 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Scheliga, F. T1 - About formation of cycles in Sn(II) octanoate-catalyzed polymerizations of lactides N2 - At first, formation of cycles in commercial poly(Llactide)s is discussed and compared with benzyl alcoholinitiated polymerizations performed in this work. This comparison was extended to polymerizations initiated with 4-cyanophenol and pentafluorothiophenol which yielded cyclic polylactides via end-biting. The initiator/catalyst ratio and the acidity of the initiator were found to be decisive for the extent of cyclization. Further polymerizations of L-lactide were performed with various diphenols as initiators/co-catalysts. With most diphenols, cyclic polylactides were the main reaction products. Yet, only catechols yielded even-numbered cycles as main reaction products, a result which proves that their combination with SnOct2 catalyzed a ring-expansion polymerization (REP). The influence of temperature, time, co-catalyst, and catalyst concentrations was studied. Four different transesterification reactions yielding cycles were identified. For the cyclic poly(L-lactide)s weight average molecular weights (Mw’s) up to 120,000 were obtained, but 1H NMR end group analyses indicated that the extent of cyclization was slightly below 100%. The influence of various parameters like structure of Initiator and catalyst and temperature on the formation of cyclic poly(Llactide)s has been investigated. Depending on the chosen conditions, the course of the polymerization can be varied from a process yielding exclusively linear polylactides to mainly cyclic polylactides. Three different reaction pathways for cyclization reactions have been identified. KW - Cyclization KW - MALDI-TOF MS KW - Polyester KW - Ring-opening polymerization KW - Transesterification PY - 2018 DO - https://doi.org/10.1002/pola.29077 SN - 0887-624X VL - 56 IS - 17 SP - 1915 EP - 1925 PB - Wiley Periodicals Inc. AN - OPUS4-46052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, Hans R. A1 - Weidner, Steffen T1 - Ring-expansion polymerization of meso-lactide catalyzed by dibutyltin derivatives N2 - Meso-Lactide was polymerized in bulk at 60, 80, and 100 °C by means of three different types of catalysts: dibutyltinsulfides (2,2-dibutyl-2-stanna-1,3-dithiolane and 2,20-dibutyl-2-stanna-1,3-dithiane), dibutyltin derivatives of substituted cate-chols (BuCa, CyCa, and BzCa), and dibutyltin derivatives of2,2 dihydroxybiphenyl (SnBi) and 2,2-dihydroxy-1,10-binaphthyl(SnNa. Only the latter two catalysts were active at 60 °C. The architecture of the resulting polylactides depends very much on the structure of the catalyst and on the temperature. At the lowest temperature (60 °C), SnBi and SnNa mainly yielded even-numbered linear chains, but SnNa also yielded even-numbered cycles at 100 °C and short reaction times. In contrast,BuCa, CyCa, and BzCa mainly yielded odd-numbered cycles, although the same catalysts yielded even-numbered linear chains when benzylalcohol was added. KW - MALDI-TOF MS KW - Cyclisation KW - Catalysts KW - Polyester KW - Polymerization PY - 2018 DO - https://doi.org/10.1002/pola.28948 SN - 1099-0518 SN - 0022-3832 VL - 56 IS - 7 SP - 749 EP - 759 PB - Wiley Periodicals Inc. AN - OPUS4-44278 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lauer, Franziska A1 - Diehn, Sabrina A1 - Seifert, Stephan A1 - Kneipp, Janina A1 - Sauerland, V. A1 - Barahona, C. A1 - Weidner, Steffen T1 - Multivariate analysis of MALDI imaging mass spectrometry data of mixtures of single pollen grains N2 - Mixtures of pollen grains of three different species (Corylus avellana, Alnus cordata, and Pinus sylvestris) were investigated by matrixassisted laser desorption/ionization time-of-flight imaging mass spectrometry (MALDI-TOF imaging MS). The amount of pollen grains was reduced stepwise from > 10 to single pollen grains. For sample pretreatment, we modified a previously applied approach, where any additional extraction steps were omitted. Our results show that characteristic pollen MALDI mass spectra can be obtained from a single pollen grain, which is the prerequisite for a reliable pollen classification in practical applications. MALDI imaging of laterally resolved pollen grains provides additional information by reducing the complexity of the MS spectra of mixtures, where frequently peak discrimination is observed. Combined with multivariate statistical analyses, such as principal component analysis (PCA), our approach offers the chance for a fast and reliable identification of individual pollen grains by mass spectrometry. KW - MALDI Imaging MS KW - Pollen grains KW - Multivariate Statistics KW - Hierarchical cluster analysis KW - Principal component analysis PY - 2018 DO - https://doi.org/10.1007/s13361-018-2036-5 SN - 1044-0305 SN - 1879-1123 VL - 29 IS - 11 SP - 2237 EP - 2247 PB - Springer AN - OPUS4-45607 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lee, Jun-Seob A1 - Radnik, Jörg A1 - Bäßler, Ralph T1 - Passivity of alloy 31 in green-death solution N2 - The passivation behavior of alloy 31 was investigated as a function of passivation potential in a green-death solution at 40 °C. The alloy 31 surface is in a stable passive state during cyclic potentiodynamic polarization. In potentiostatic polarization of alloy 31, passive current density increases with an increase in the passivation potential. Electrochemical impedance spectroscopy (EIS) and Mott–Schottky (M–S) analysis showed that a more defective n-type semiconductive passive film forms as the potential increases. X-ray photoelectron spectroscopy (XPS) revealed that passive film consists of mainly chromium and minor iron and nickel oxides. The increase of the applied potential is considered to be a reason for the change in passive film stability. KW - Passive film KW - Steel KW - Alloy 31 KW - X-ray photoelectron spectroscopy PY - 2018 DO - https://doi.org/10.1002/maco.201709996 SN - 0947-5117 SN - 1521-4176 VL - 69 IS - 9 SP - 1218 EP - 1226 PB - Wiley-VCH CY - Weinheim AN - OPUS4-45938 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen T1 - Cyclic poly(L-lactide)s via simultaneous ROP and polycondensation (ROPPOC) catalyzed by dibutyltin phenoxides N2 - Starting from dibutyltin oxide, four catalysts were synthesized, namely the dibutyltin bisphenoxides of Phenol (SnPh), 4-chlorophenol (SnCP), 4-hydroxybenzonitrile (SnCN) and pentafluorophenol (SnOPF). With the first three catalysts polymerizations of L-lactide at 160 °C in bulk yielded large fraction of linear chains having phenylester end groups at short reaction times. At longer times the fraction of cycles considerably increased at the expense of the linear chains, when SnCN was used as catalyst. With SnOPF only cyclic polylactides were obtained at low Lac/Cat ratios (< 400) with weight average molecular weights (Mw) up to 90 000 Da, whereas for high Lac/Cat ratios mixtures of cyclic and linear chains were found. Polymerizations in solution enabled variation of the molecular weight. Polymerizations of meso-lactide at temperatures down to 60 °C mainly yielded even-numbered linear chains supporting the postulated ROPPOC mechanism. KW - Cyclization KW - MALDI-TOF MS KW - Polycondensation KW - Ring-opening Polymerization KW - Polylactide PY - 2018 DO - https://doi.org/10.1016/j.eurpolymj.2018.10.005 SN - 0014-3057 IS - 109 SP - 360 EP - 366 PB - Elsevier AN - OPUS4-46263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Aristia, Gabriela T1 - Electrochemical deposition of polyaniline on carbon steel for corrosion study in geothermal solution N2 - Polyaniline has been widely developed for many applications, e.g., sensor, supercapacitor component, electrochromic devices, and anticorrosion pigments [1]. Although the addition of polyaniline pigment in organic coatings has been an alternative for corrosion protection in industrial application, the protection mechanism is still not fully understood [2]. Herein in this study, as a part of the development of polyaniline/silicon dioxide coating for geothermal application, polyaniline has been deposited electrochemically on carbon steel surface and tested in geothermal solution to study the contribution of polyaniline in the corrosion protection of a polyaniline-based composite in the geothermal system. The electrochemical deposition was carried out by immersing carbon steel in 0.1 M oxalic acid and 0.05 M aniline, with the polarization potential of -0.6 – 1.5 V vs. Ag/AgCl, and a scan rate of 10 mV/s. To observe the surface/interface reaction between the electrolyte and electrode surface during the electrochemical polymerization, electrochemical impedance spectroscopy (EIS) measurement was applied after each cycle. For corrosion study in the geothermal application, this experiment used an artificial geothermal solution with the composition of 1,500 mg/l Cl-, 20 mg/l SO42-, 15 mg/l HCO3-, 200 mg/l Ca2+, 250 mg/l K+, and 600 mg/l Na+, and pH 4 to simulate a geothermal brine found in Sibayak, Indonesia. Electrochemical measurements were performed by monitoring the open circuit potential over seven days, with the interruption of EIS every 22 hours. The experiments were performed at room temperature and 150 °C (1 MPa) in a free oxygen environment. Polyaniline coated carbon steel is more durable in a room temperature environment compared to 150 °C, which could be caused by the iron oxalate dissolution at elevated temperature. This degradation was further proven by the impedance spectra, which showed a reduction of approximately ten times for specimens measured at 150 °C as compared to the specimens measured at room temperature. T2 - 4th International Conference on Functional Materials Science 2018 (ICFMS 2018) CY - Bali, Indonesia DA - 13.11.2018 KW - Polyaniline KW - Electrochemical deposition KW - Corrosion PY - 2018 AN - OPUS4-46742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Le, Quynh Hoa T1 - Droplet corrosion of CO2 transport pipeline steels N2 - In this work, the focus was set on the corrosion process of condensate as drops on the surface of carbon steels (X52, X70), martensitic steel UNS S41500, and superaustenite UNS 08031 in CO2 atmosphere with impurities at 278 K (to simulate the transportation condition in a buried pipeline). Exposure tests were performed at both normal pressure and high pressure where CO2 is supercritical or in dense phase. The drop, 1 ‑ 10 µL in volume, was prepared by dropping CO2 saturated ultra-pure water onto the surface of steel coupons in a one-liter-autoclave. The CO2 gas stream, simulating the oxyfuel flue gas with varying concentration of impurities (SO2 and O2), was then pumped into the autoclave to observe the condensation and corrosion impacts of impurities. Comparable exposure tests were carried out with the same gas mixture and the same volume of water as vapor to observe the drop formation and the corrosion process that follows. The wettability and stability of drops on the surface of steel coupons in CO2 supercritical/dense phase environment was evaluated additionally by contact angle measurement. T2 - NACE International Annual Corrosion Conference CY - Phoenix, AZ, USA DA - 15.04.2018 KW - CCUS KW - Supercritical/dense phase CO 2 KW - Carbon steels KW - Martensitic steel KW - Superaustenite steel KW - Droplet corrosion PY - 2018 AN - OPUS4-44922 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Piechotta, Christian T1 - Bewitterungsszenarien im Vergleich – Veränderungen in der Oberflächenmorphologie von Polypropylen (PP) und Polystyrol (PS) unter dem Aspekt des Austrags von polybromierten Flammschutzmitteln N2 - In addition to previously reported results on the simulated aging of polystyrene samples (PS) containing 1 wt. % hexabromocyclododecane (HBCD), we present the first results of our investigations of polypropylene (PP)-samples containing 0.1 wt. % BDE-209. All studied polymer samples were exposed to a defined weathering schedule in a climate chamber in accordance to regulation EN ISO 4892-3:2006.For the determination of BDE-209 in the collected rain water samples derived from the used climate chamber, the samples were prepared in accordance with a validated protocol. Before the analyses, each sample was spiked with 2 µL of isotopically labeled BDE-209 (13C10-BDE-209) to serve as internal standard (ISTD) in the performed stable isotope dilution analysis. Subsequently the samples were extracted with isooctane, the obtained aliquots of the extracts were concentrated to 200 µL and 2 µL of the resulting solution were injected to the GC/MS for quantification. Additionally, the total bromine contents are monitored for the aged and untreated samples using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) as well as X-ray fluorescence analysis (XRF) as non-destructive and rapid method. Furthermore, results from surface analysis using environmental scanning electron microscopy (ESEM) for morphological characterization of the aged and untreated samples were presented and discussed. In general, the resulting data from the accelerated aging will be compared to those from the natural weathering experiments (“atmospheric exposure”, in soil). The atmospheric exposure was performed by placing the samples on a weathering rack, which is aligned in SW direction (in a 45° angle to the horizon). The weathering data were regularly recorded by Deutscher Wetterdienst at this site. The surfaces of the test specimens (aged and stored references) were analyzed by ESEM as well as by LA-ICP-MS and by XRF. The surface of PS and PP specimens aged outdoors present the aging under real conditions and allow the comparison to the accelerated aged specimens by means of the weathering chamber. This way, we explore the efficiency of the accelerated aging procedure, which provides the advantage of well-defined and reproducible conditions compared to natural weathering, as a tool for testing different plastic materials. Additionally “in soil” experiments were conducted in-door in a well characterized testing soil. The soil (boulder-clay, sand with 12 % loam, particle size in total 0.2-4 mm) is filled in a free-draining concrete basin inside of an air-conditioned room. In this manner, TOC, water capacity and humidity are recorded parameters. To assure a washing out process from the samples by the raining water, the target water content is calculated to 8%. The actual humidity is measured by a tensiometer, assuring the duration of the raining period. The water content is additionally monitored by weight of the basin, capturing water from raining periods. The correct humidity is a fundamental parameter for biological activity. Samples of PS resp. PP were of dimension 10x1cm and 5 specimens were placed up to the half in the soil per basin. Microbial activity of the soil, monitored by the reference polyurethane, sets HBCD resp. BDE-209 of the samples free and will be leached from the samples by raining water. Thereafter these will be captured by passive samplers placed in a distinct distance to the samples in the soil. The “in soil” experiments are complementary to the weathering experiments due to the biological activity in the soil. These experiments simulate the fate of the brominated flame retardants in the biosphere. N2 - Gegenstand der vorzustellenden Arbeiten ist die Prüfung der Umweltbeständigkeit und -verträglichkeit von Materialien und Produkten hinsichtlich der Emission von potenziellen Schadstoffen in die Umwelt. Hierzu werden chemisch-physikalische Einflüsse (Bewitterung) und mikrobielle Beanspruchungen an Modellmaterialien evaluiert. So werden die Freisetzungsraten von Schadstoffen in Abhängigkeit der Beanspruchung beschrieben. Als Modellmaterialien kommen die Polymere Polystyrol (PS) und Polypropylen (PP) zum Einsatz, die jeweils mit polybromierten Flammschutzmitteln (PBFSM) versehen sind. Synergistische Effekte der Bewitterungsparameter und der mikrobiologischen Beanspruchung sollen dabei ebenso betrachtet werden, wie die gezielte Alterung. Auch findet eine Beschreibung des Verhaltens der ausgetragenen Schadstoffe in den Umweltkompartimenten Boden oder Wasser statt. Hier sind mit Hilfe der zu entwickelnden Screening- und non-Target-Analyseverfahren die Transformation und der Metabolismus durch Mikroorganismen zu beschreiben. Auch soll mit Hilfe der RFA und der LA-ICP-MS die Abreicherung der PBFSM in den Modellmaterialien beschrieben werden. Aus den Ergebnissen sollen Korrelationen zwischen den künstlichen Alterungsverfahren und realen Szenarien abgeleitet werden. T2 - 47. Jahrestagung der GUS 2018 CY - Stutensee - Blankenloch, Germany DA - 21.03.2018 KW - Polypropylen KW - Polystyrol KW - Flammschutzmittel KW - XRF KW - LA-ICP-MS PY - 2018 AN - OPUS4-47024 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Breitenbach, Romy T1 - Biochemische und physiologische Charakterisierung der extrazellulären Matrix eines Modellbiofilms N2 - An der Grenzschicht zwischen einer festen Oberfläche und der umgebenden Luft wachsende subaerische Biofilme (SAB) zeichnen sich durch eine erhöhte Toleranz gegenüber extremen Umweltbedingungen und dem Eintrag von Bioziden aus. Dieser Schutz vor äußeren Umwelteinflüssen wird vornehmlich durch den Beitrag von extrazellulären polymeren Substanzen (EPS) und Pigmenten, wie Melanin und Carotinoiden, vieler unterschiedlicher Organismen gewährleistet. Deren Synthese wird wiederum durch intrazelluläre Botenstoffe reguliert. Das Cyanobakterium Nostoc punctiforme und der mikrokoloniale Pilz Knufia petricola, als Partner eines etablierten SAB-Modells und Vertreter zweier typischer Organismengruppen in SAB, wurden genutzt, um Botenstoffe und Pigmente genetisch zu manipulieren und die Biofilmmatrix dieser Mutanten strukturell zu untersuchen. In dieser Arbeit konnten erstmals die EPS beider Organismen extrahiert und die Struktur der extrazellulären Polysaccharide beschrieben werden. Daneben wurden die extrazellulären Polysaccharide von K. petricola Wildtyp mit denen verschiedener Pigmentmutanten verglichen. Das Fehlen des Schutzpigmentes Melanin führte zu einer ausgeprägteren extrazellulären Matrix in den Biofilmen. Gleichzeitig änderte sich die Struktur der extrazellulären Polysaccharide. Während der Wildtyp zu ~80% ein α-Glucan und zu ~20% ein α/β-Galaktomannan sekretierte, war der Anteil des Galaktomannans bei den Melaninmutanten erhöht. Das Ausschalten der Carotinoid-Synthese hatte jedoch keinen Einfluss auf die Beschaffenheit der extrazellulären Polysaccharide. Ein deutlich komplexeres extrazelluläres Polysaccharid aus acht verschiedenen Monosaccharid-Einheiten bildete N. punctiforme. Durch die Überproduktion des bakteriellen sekundären Botenstoffes c-di-GMP konnte zudem ein grundlegender Einfluss auf die Reaktion des Cyanobakteriums gegenüber externen Signalen und die damit verbundene Zelldifferenzierung gezeigt werden. Ein artifiziell erhöhtes c-di-GMP-Level in den Zellen führte zur Ausbildung eines sessilen Lebensstils durch Hemmung der Differenzierung motiler Hormogonien und vermehrte Produktion von EPS. Die Struktur der extrazellulären Polysaccharide wurde dadurch nicht verändert. Neben der strukturellen Analyse konnten die Veränderungen der extrazellulären Matrix beider Organismen zusätzlich durch mikroskopische Methoden visualisiert werden. Beide Organismen steuern komplexe Polymere, deren Produktion maßgeblich mit intrazellulären Faktoren verknüpft ist, zu der extrazellulären Matrix des Modellbiofilms bei. KW - Biofilm KW - EPS KW - Extrazelluläre Polysaccharide PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471747 SP - 1 EP - 198 CY - Berlin AN - OPUS4-47174 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lüchtenborg, Jörg T1 - Additive manufacturing of dense ceramics with laser induced slip casting (LIS) N2 - Most additive manufacturing processes which produce dense ceramics are nowadays limited in size because of inevitable post-processing steps like for example binder removal in stereolithography. The additive manufacturing of voluminous ceramic parts is realized by powder bed based processes which, however, generate parts with residual porosity. Via infiltration these parts can be processed to dense parts like for example SiC but this is not possible for all ceramics like for example Si3N4. There is a lack of methods for the additive manufacturing of dense voluminous parts for most ceramics. We have developed a new additive manufacturing technology, the Laser Induced Slip casting (LIS), based on the layerwise deposition of slurries and their local drying by laser radiation. Laser Induced Slip casting generates ceramic green bodies which can be sintered to dense ceramic components like traditional formed ceramic powder compacts. We will introduce the LIS technology, green bodies and sintered parts will be shown and their microstructure and mechanical properties will be discussed. T2 - yCAM (Young Ceramists Additive Manufacturing Forum) CY - Padua, Italy DA - 03.05.2018 KW - Additive manufacturing PY - 2018 AN - OPUS4-45782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witt, Julia T1 - AFM-Untersuchungen von funktionellen Beschichtungen und Strukturänderungen unter mechanischer Beanspruchung N2 - Die Rasterkraftmikroskopie (AFM) hat sich in den letzten Jahren als eine vielseitige Abbildungstechnik von Oberflächen mit einer sehr hohen Ortsauflösung etabliert. Über die Untersuchung der reinen Oberflächentopographie sind erweiterte Modi in der Lage, gleichzeitig Informationen über die elektrischen und magnetischen Eigenschaften sowie Adhäsionsprozesse auf Oberflächen zu liefern. Interessanter wird es, wenn das AFM mit geeigneten Messzellen für in-situ-Untersuchungen in kontrollierten Atmosphären oder in Elektrolyten unter elektrochemischer Kontrolle ausgestattet ist. Dies ermöglicht die Untersuchung von Korrosions- und Adhäsionsprozessen unter Bedingungen, die die Betriebsumgebung repräsentieren. Ein aktueller Forschungsschwerpunkt unseres Fachbereiches liegt in den Untersuchungen der Deformationseigenschaften von Funktionsschichten auf Leichtmetalllegierungen, sowie in situ Untersuchungen des Korrosionsverhaltens unter kombinierter korrosiver und mechanischer Beanspruchung mittels AFM. Durch die Integrierung eines Zug-Druckmoduls in den Probentisch des Rasterkraftmikroskops haben wir jetzt die Möglichkeit, verschiedene Materialien uniaxialen Umformversuchen mit bis zu 5 kN Kraft zu unterziehen. Dabei können unter anderem auch zyklische Belastungen genutzt werden, um Ermüdungsprozesse zu simulieren. Da die Messungen in situ ohne die De- und Remontage der Probe durchgeführt werden, ermöglicht der Aufbau nicht nur Messungen mit präziser Positionssteuerung, sondern auch die Untersuchung von Prozessen im elastischen Bereich, die für die Aufklärung der Mechanismen, die zu Ermüdungsversagen führen, entscheidend sind. Die Posterpräsentation wird detaillierte Informationen zum neuen AFM-Setup liefern und unsere aktuellen Ergebnisse zur Verformung dünner Schutzschichten auf AA2024-T3 zusammenfassen. T2 - Hybrid, Materials and Structures CY - Bremen, Germany DA - 18.04.2018 KW - Kelvinsondenkraftmikroskopie KW - Funktionelle Beschichtungen KW - Kombinierete korrosive und mechanische Beanspruchung KW - Lokale Korrosion KW - Delamination KW - Deformation PY - 2018 AN - OPUS4-46522 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Piechotta, Christian T1 - TF-Projekt MaUS: Material und Umweltsimulation N2 - Gegenstand des Projekts ist die Prüfung der Umweltbeständigkeit und -verträglichkeit von Materialien und Produkten hinsichtlich der Emission von potenziellen Schadstoffen in die Umwelt. Hierzu werden chemisch-physikalische Einflüsse (Bewitterung) und mikrobielle Beanspruchungen an Modellmaterialien evaluiert. So werden die Freisetzungsraten von Schadstoffen in Abhängigkeit der Beanspruchung beschrieben. Als Modellmaterialien kommen die Polymere Polycarbonat, Polytetrafluorethylen, Polystyrol und Polypropylen zum Einsatz. Synergistische Effekte der Bewitterungsparameter und der mikrobiologischen Beanspruchung sollen dabei ebenso betrachtet werden, wie die gezielte Alterung. Auch findet eine Beschreibung des Verhaltens der ausgetragenen Schadstoffe in den Umweltkompartimenten Boden oder Wasser statt. Hier sind mit Hilfe der zu entwickelnden Screening- und non-Target-Analyseverfahren die Transformation und der Metabolismus durch Mikroorganismen zu beschreiben. Aus den Ergebnissen sollen Korrelationen zwischen den künstlichen Alterungsverfahren und realen Szenarien abgeleitet werden, die es gestatten, Schnellprüfverfahren zu etablieren, die die Simulation der realen Beanspruchungen im Zeitraffermodell anwendbar machen. Somit sollen standardisierbare Schnellbeanspruchungs-verfahren erarbeitet werden, die als Prüfeinrichtungen etabliert werden und von externen Auftraggebern zur Prüfung der Umweltbeständigkeit und -verträglichkeit von neuen Materialien genutzt werden können. Die Umweltwirkungen (chemisch-physikalisch und mikrobiologisch) sollen so definiert eingesetzt werden, dass eine reproduzierbare Prüfung möglich wird. Aus diesen Verfahren und Methoden sollen Normen abgeleitet werden, die eine standardisierte Materialprüfung ermöglichen. T2 - Projektmeeting BAM - Covestro CY - Leverkusen, Germany DA - 29.05.2018 KW - Umweltsimulation KW - Schadstoffaustrag PY - 2018 AN - OPUS4-47025 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altenburg, Simon A1 - Maierhofer, Christiane T1 - ProMoAM - Verfahrensentwicklung für das Prozessmonitoring in der additiven Fertigung N2 - Verfahren zum in-situ Monitoring der Prozess- und Bauteilparameter sollen Fehlstellen und Inhomogenitäten bereits während der Fertigung nachweisen und zukünftig auch die Regelung der Prozessparameter ermöglichen. T2 - Challenges in Additive Manufacturing: Innovative Materials and Quality Control, Berlin Partner Workshop CY - Berlin, Germany DA - 12.09.2018 KW - Additive Fertigung KW - Prozessmonitoring KW - ProMoAM PY - 2018 AN - OPUS4-46300 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ramirez Caro, Alejandra A1 - Pauli, Jutta A1 - Mota, Berta A1 - Crasselt, Claudia A1 - Artemeva, Elena A1 - Schmidt, Wolfram A1 - Resch-Genger, Ute T1 - A Spectroscopic Study of the Superplasticizer Effect on Early Cement Hydration N2 - Organic/inorganic mixtures were prepared from ordinary Portland cement (OPC), water (w/c 0.22), a fluorescent dye in aqueous solution (stable at alkaline pH; BAM-I), and two different comb shape polycarboxylates (PCEs), i.e., high charge (PCE-HC) and low charge (PCE-LC), respectively. Rheological and calorimetric measurements were performed prior to optical studies in order to select PCE concentrations. Absorption and fluorescence spectroscopy of the system OPC + BAM-I (CBAM-I) revealed maxima of dye BAM-I located at 645 nm and 663 nm, respectively. In presence of PCE-HC and PCE-LC, these mixtures displayed a small red shift in reflectance and a faster decrease in intensity compared to studies with CBAM-I; however, only slight differences were observed between the different PCEs. With time, all systems exhibited a decrease in intensity of BAM-I in absorption/reflectance and emission. This could be caused by dye adsorption and possibly decomposition when in contact with cement particles or hydration products. T2 - The Sixth International Symposium on Nanotechnology in Construction (NICOM6) CY - Hong Kong, China DA - 02.12.2018 KW - Cement KW - Optical Spectroscopy KW - Dye KW - Hydration PY - 2018 SP - 1 EP - 9 AN - OPUS4-49378 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Mota, Berta A1 - Ramirez Caro, Alejandra T1 - The action of aggregates on concrete rheology N2 - Most factors acting on concrete rheology work at an extremely small-scale level. Influencing factors in the millimetre or centimetre area are essentially restricted to sand and aggregates. The latter, however, make up 50 to 70% of the total volume of most concretes – a fact often ignored in research on controlling concrete processing properties. Whereas suitably chosen concrete admixtures and additives can influence rheology in a very targeted manner, sand and aggregates are less suitable for controlling rheology but nonetheless contribute to the rheology of the Overall system. The actions of sand and aggregate can impose themselves upon the actions of admixtures and additives and, in unfavourable circumstances, even render them redundant. For this reason, any results concerning the processability of binding agent systems can only be transferred to concrete with great care. It is important to better understand the action of sand and aggregates in order to be able to harmonise them in such a way that they complement the action of superplasticisers positively, instead of working against them. Savings on costs can also be made by this targeted fine-tuning. KW - Rheology KW - Aggregates KW - Viscosity KW - Yield stress KW - Concrete PY - 2018 VL - 3 SP - 42 EP - 49 PB - ad-media GmbH CY - Cologne AN - OPUS4-47045 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Olonade, Kolawole Adisa A1 - Tchetgnia Ngassam, Ines Leana A1 - Mbugua, Rose A1 - Athman Mwende, Carol A1 - Kühne, Hans-Carsten ED - Ludwig, Horst-Michael T1 - Pflanzenbasierte Betonzusatzmittel für Hochleistungsbeton N2 - Während für die Bauwirtschaft in den meisten Ländern der nördlichen Halbkugel die Instandhaltung bestehender Strukturen und Infrastruktur im Vordergrund steht, geht es in vielen Ländern der Südhalbkugel in der Hauptsache um die Schaffung von Bauwerken und Infrastruktur zur Verwirklichung angemessener Lebensbedingungen, was wiederum das schnelle Wirtschaftswachstum weiter befeuert. Beton ist als Massenbaustoff, trotz landläufig anderer Bewertung, aufgrund seines im Vergleich zu anderen Baustoffen günstigen CO2-Footprints und der globalen Verfügbarkeit hierbei aktuell ohne Alternative. Allerdings ist Beton nach Wasser das am zweithäufigsten genutzte Produkt auf Erden [1] und die globale Nachfrage und Produktion steigt dramatisch. Dies hat Konsequenzen für das globale Klima, denn gerade die als Bindemittel eingesetzten Portlandzemente verursachen bei ihrer Herstellung selbst unter modernsten Produktionsbedingungen große Mengen an CO2. Deshalb müssen für zukünftige nachhaltigere Technologien neuartige Betone entwickelt werden, die bei gleicher oder verbesserter Leistungsfähigkeit, einen geringeren Bedarf an Portlandzement aufweisen. Um den CO2-Ausstoß, der mit der Betonherstellung verbunden ist zu minimieren, müssen Anteile an Portlandzement im Bindemittel reduziert und durch nachhaltigere Ersatzstoffe ausgetauscht werden. Darüber hinaus muss das eingesetzte Bindemittel im Beton so effizient wie möglich ausgenutzt werden. Das heißt, ein Bauteil oder Bauwerk sollte gerade so viel Bindemittel enthalten, wie für die Tragfähigkeit und Dauerhaftigkeit erforderlich ist. Hierfür erscheint der Einsatz von leistungsfähigen bauchemischen Produkten unumgänglich. Diese können zum einen die veränderten Verarbeitungseigenschaften, die Zementersatzstoffe mit sich bringen, ausgleichen und gleichzeitig helfen, den Gesamtwassergehalt zu minimieren, so dass das Bindemittel seine maximale Leistungsfähigkeit erzielt. Fließmittel sind aktuell die wichtigsten Zusatzmittel für Beton. Sie reduzieren den Wasserbedarf und ermöglichen, Zement im Beton effizienter auszunutzen. Darüber hinaus sind Stabilisierer wichtig zur Erhöhung der Robustheit, insbesondere im Hinblick auf die bautechnischen Herausforderungen der Zukunft – vom Pumpen über weite Distanzen, dem Spritzen, dem Betonieren bei extremen Klimabedingungen bis hin zum 3D-Druck. T2 - ibausil CY - Weimar, Germany DA - 12.09.2018 KW - Bauchemie KW - Zusatzmittel KW - Rheologie KW - Polysaccharide KW - Akaziengummi KW - Triumfetta Pendrata A. Rich PY - 2018 SN - 978-3-00-059950-7 VL - 20 SP - 1-874 EP - 1-885 CY - Weimar AN - OPUS4-47048 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Crasselt, Claudia A1 - Schmidt, Wolfram A1 - Sturm, Heinz ED - M. Tyrer, ED - E. Ganjian, ED - West, A. T1 - Influence of rheology modifying admixtures on hydration of cementitious suspensions N2 - The presence of polycarboxylate ether (PCE) based superplasticizers (SPs) has an enormous influence on the early hydration of cement. The hydration is retarded and the timing of formation and the morphology of hydrates is affected. This short paper presents experimental results about the influence of delayed Addition time of PCE SPs on hydration of cement and tricalcium aluminate (C3A) pastes, investigated by isothermal heat flow calorimetry. For cement pastes the hydration is retarded with SP, whereby the high charge PCE has a stronger retarding effect than the low charge PCE. With delayed PCE addition the cement shows a less retarded setting than with simultaneous addition. The alteration caused by PCE is much more pronounced for C3A and gypsum mixes than for cement. If the SP is added simultaneous, the exothermic peak of C3A is retarded. However, with delayed addition of SP the hydration is shortened, the gypsum depletion is fastened and the exothermic peak occurs less retarded or even accelerated compared to simultaneous addition. It is obvious that for C3A pastes there is less retardation the later the Addition of SP. Furthermore, the PCE alter the hydration of C3A when added delayed and exhibit changes in kinetics and hydration rates. The rate of reaction in the second stage is lower, discernible in decreased slopes and broader peaks. Besides this, a distinct ramp in the C3A heat flow curves within the first stage of C3A hydration occurs for all pastes with delayed addition of SP, which suggests an accelerated ettringite formation. T2 - 38th Cement and Concrete Science Conference CY - Coventry, UK DA - 10.09.2018 KW - Cement hydration KW - Polycarboxylate ether KW - C3A hydration PY - 2018 SN - 978-1-84600-088-1 SP - 64 EP - 67 CY - Coventry, UK AN - OPUS4-45995 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shamsuddoha, Md T1 - Superplasticizer and shrinkage reducing admixture dosages for microfine cement in grout systems N2 - Grouts have numerous applications including crack repair as maintenance in construction industries. Microfine cements are intensively used for high strength mortar and grout products. They are ideal for injection grouting in structural repair. Such grouts should have suitable rheological properties to be injectable, especially those used in repair and rehabilitation. The use of superplasticizers (SP) in these products is thus becoming increasingly crucial to achieve favorable workability and viscosity properties. A difficulty in such grouts is the plastic shrinkage due to finer particles used. It is thus necessary to determine optimum SP and shrinkage reducing admixture (SRA) dosages for a microfine cement based grout. In this study, a saturation dosage was decided from two Polycarboxylate ether (PCE) based SPs in relation to neat cement using slump flow and rheological parameters. A range of grout mixtures was formulated containing micro silica (MS) and fly ash (FA), and tested for suitable rheological and mechanical parameters. Based on the results, a grout mixture with MS and FA was selected to determine optimum SRA content. According to the results, a SP dosage of 3% by weight of neat cement is sufficient to achieve saturation. The grout material including MS and FA can produce comparable properties to neat cement grout. MS is found to improve compressive strength within the range considered, whereas a higher FA content provides favourable rheological properties. Finally, a SRA dosage of 4%, which could reduce the shrinkage by about 43% after 28d days, is determined for the grout system. T2 - 2nd International Conference on Building Materials and Materials Engineering (ICBMM 2018) CY - University of Lisbon, Portugal DA - 26.09.2018 KW - Grout KW - Mix design KW - Shrinkage KW - Crack repair KW - Microfine cement PY - 2018 AN - OPUS4-46155 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shamsuddoha, M. T1 - Workability and mechanical properties of ultrafine cement based grout for structural rehabilitation: A parametric study on the partial replacement with SCMs N2 - Grouting is a universal repair and strengthening technique, which is constantly used for structural remediation of concrete components, trenches, mine subsidence, dam joints, restoration of masonry structures, and geological stabilizations. Having an extremely small particle size of only few microns, ultrafine cements are ideal for grouting applications due to their superior permeability and compressive strength properties of the hardened cement paste compared to that of the less-expensive, but coarser ordinary Portland cements. Supplementary cementitious materials (SCMs) are often used to replace ultrafine cement in order to modify certain properties and to reduce costs. The aim of this experimental study is to investigate the effect of three supplementary materials: microsilica (MS), fly ash (FA), and metakaolin (MK) on the workability, and mechanical properties of an ultrafine cement based grout with a constant water-binder ratio and constant superplasticizer content. Maximum percentages of replacement with ultrafine cement were 6% by volume of cement for MS and 16% for FA, and MK. In general, results suggest that the workability is improved by addition of FA, whereas is reduced, when modified with MS and MK. The compressive strength of grout after cement replacement remains comparable to that of pure cement grout. However, there is a tendency of the MS to positively affect the compressive strength opposite to FA, whereas flexural strength is positively affected by FA. Based on the results, it is evident that grouts with Hägerman cone flow more than 500 mm and compressive strength of more than 90 MPa after 28 days can be produced. T2 - International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) CY - Cape Town, South Africa DA - 19.11.2018 KW - Analysis of variance KW - Box-Behnken KW - Grouting KW - Repair KW - Supplementary cementitious materials PY - 2018 AN - OPUS4-46712 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Leinitz, Sarah T1 - Einfluss der wässrigen Phase von Zementleim und Polycarboxylatethern auf die Rheologie und die frühe Hydratation von Zement N2 - Die Rheologie von fließfähigen zementären Systemen mit Fließmitteln wird durch eine Vielzahl parallel stattfindender Effekte beeinflusst. Zu diesen Effekten zählen Wechselwirkungen zwischen den Polymeren und Ionen in der Porenlösung, frühe Phasenbildung, zeitabhängige und kompetitive Adsorption zwischen anionischen Polymeren und Sulfationen, Bildung von Phasen in der Porenlösung sowie Morphologieänderungen an Partikeloberflächen. Die frühe Hydratation von Zement, die durch Lösungs- und Fällungsprozesse angetrieben wird, beeinflusst diese Effekte erheblich. Das permanente Ungleichgewicht der Porenlösung führt zu Veränderungen der Partikeloberflächen, welches widerum zur Folge hat, dass rheometrische Messungen dieser Zementleime anfällig für Streuungen sind. Um die Einflüsse aus der Zementhydratation zu minimieren, wurden die rheometrischen Untersuchungen mit Zement in Wasser, wässriger Phase von Zementleim bzw. mit vorhydratisiertem Zement durchgeführt. Zusätzlich wurden die gleichen Systeme mit Zugabe von Polycarboxylatethern untersucht. Die Ergebnisse zeigen, dass die Leime mit Wasser niedrigere Werte für Fließgrenze und plastische Viskosität aufweisen, als die Systeme mit der wässrigen Phase von Zementleim. Während die Polymere eine Verminderung der Fließgrenze zur Folge hatte, war die Wirkung von Polymeren auf die plastische Viskosität vernachlässigbar. Zusätzlich wurde die frühe Hydratation unter Verwendung von Wärmeflusskalorimetrie, Rasterelektronenmikroskopie und Nadeleindringtiefe beobachtet. T2 - 20. Internationale Baustofftagung CY - Weimar, Germany DA - 12.09.2018 KW - Rheologie KW - Polycarboxylatether KW - Zementleim KW - Fließmittel PY - 2018 AN - OPUS4-45974 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Leinitz, Sarah T1 - Assessment of rheological effects in the binder on the rheology of mortar N2 - In the last years flowable concrete has become increasingly important in applications such as, for systems with highly reinforced concrete with a complicated formwork, or sprayed concrete and 3D-printing of concrete. For all these applications it is necessary to have tailored rheological properties. Rheology can be described by values of yield stress and plastic viscosity, which can be determined for example by evaluation of rheometer measurements. But for different materials various rheometers with different geometries and stirrers are being used. To see the effects from paste in concrete, it is necessary to investigate mixes of paste, mortar and concrete, stepwise. But currently there exists no device, which is calibrated for these different systems at once. Due to this fact, conventional tests such as V-funnel efflux-time and flow diameter were determined, as well as rheometer data in different cell sizes and geometries. In this study the assessment of rheological effects in the binder on the rheology of mortar was investigated by using combination of two rheometers. T2 - Rheologische Messungen an Baustoffen 2018, 27. Workshop und Kolloquium CY - Regensburg, Germany DA - 07.03.2018 KW - Rheology KW - Cement KW - Mortar PY - 2018 AN - OPUS4-44447 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ramirez Caro, Alejandra A1 - Mota, Berta A1 - Artemeva, E. A1 - Pauli, Jutta A1 - Schmidt, Wolfram A1 - Resch-Genger, Ute T1 - A spectroscopic study of the superplasticizer effect on early cement hydration N2 - Organic/inorganic mixtures were prepared from ordinary Portland cement (OPC), water (w/c 0.22), a fluorescent dye in aqueous solution (stable at alkaline pH; BAM-I), and two different comb shape polycarboxylates (PCEs), i.e., high charge (PCE-HC) and low charge (PCE-LC), respectively. Rheological and calorimetric measurements were performed prior to optical studies in order to select PCE concentrations. Absorption and fluorescence spectroscopy of the system OPC + BAM-I (CBAM-I) revealed maxima of dye BAM-I located at 645 nm and 663 nm, respectively. In presence of PCE-HC and PCE-LC, these mixtures displayed a small red shift in reflectance and a faster decrease in intensity compared to studies with CBAM-I; however, only slight differences were observed between the different PCEs. With time, all systems exhibited a decrease in intensity of BAM-I in absorption/reflectance and emission. This could be caused by dye adsorption and possibly decomposition when in contact with cement particles or hydration products. T2 - 20. Internationale Baustofftagung CY - Weimar, Germany DA - 12.09.2018 KW - Optical spectroscopie KW - Cement hydration KW - Dyes PY - 2018 SN - 978-3-00-059950-7 VL - 20 SP - 1 EP - 6 PB - F.A. Finger-Institut für Baustoffkunde CY - Weimar AN - OPUS4-46277 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Wolfram A1 - Tchetgnia Ngassam, Ines Leana A1 - Olonade, K. A. A1 - Mbugua, R. A1 - Kühne, Hans-Carsten T1 - Plant based chemical admixtures – potentials and effects on the performance of cementitious materials N2 - While today, engineers can choose from a wide range of rheology modifying admixtures, in some parts of the world, these are difficult to access, due to their complex processing. However, alternatives can be bio‐based polymers such as polysaccharides from various sources. These are easily accessible all over the world, do not demand for complicated processing, and typically they are more sustainable than many established materials, which are crude oil‐based. The paper presents the effects of acacia gum, cassava starch and the gum of triumfetta pendrata A. Rich on the rheological performance of cementitious systems. It is shown that acacia gum can be as efficient as polycarboxylate based superplasticisers, cassava starch can reduce the yield stress slightly with little effect on the plastic viscosity, and the gum of triumfet ta pendrata A. Rich increases the thixotropy of cement pastes with plasticizing polymers significantly. KW - Polysaccharides KW - Rheology KW - Cement KW - Chemical admixtures KW - Bio-based concrete PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476748 DO - https://doi.org/10.21809/rilemtechlett.2018.83 VL - 3 SP - 124 EP - 128 PB - RILEM S.A.R.L. CY - Paris AN - OPUS4-47674 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Tchetgnia Ngassam, Ines A1 - Breitschaft, G. A1 - Virchow, S. ED - Diouri, A. ED - Boukhari, A. ED - Ait Brahim, L. ED - Bahi, L. ED - Khachani, N. ED - Saadi, M. ED - Aride, J. ED - Nounah, A. T1 - Challenges of the growing African cement market – environmental issues, regulative framework, and quality infrastructure requirements N2 - The African cement, concrete and construction business is growing at rapid pace. The cement sales are expected to grow rapidly until 2050. The number of newly built cement plants increases dramatically and in addition more cements are being imported from outside the continent, e.g. from Turkey, Pakistan, Indonesia, and China, driven by overcapacities in the countries of origin. This causes a high number of potentials and challenges at the same time. Newly built cement plants can operate directly at best technological state of the art and thus incorporate more sustainable technologies as well as produce new and more sustainable products such as cements blended with sustainable supplementary cementitious materials such as calcined clays, and industrial or agricultural by products. At the same time the new variety of binding agent as well as the international imports, which are driven by price considerations, make the cement market prone to quality scatter. This puts pressure on the quality control regulations and institutions to ensure safety of construction, healthy application, and environmental safety for the population. The paper presents possible solutions to build up the rapidly increasing African cement production more sustainably than in the rest of the world as well as the related challenges and obstacles that need to be overcome. Based on experiences with a series of pan-African cement testing laboratory proficiency schemes conclusions are made on technical, regulative and political level. T2 - 2nd International Congress on Materials & Structural Stability (CMSS-2017) CY - Rabat, Morocco DA - 22.11.2017 KW - Quality Infrastructure KW - Africa KW - Proficiency Testing KW - Cement KW - Admixtures PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444330 DO - https://doi.org/10.1051/matecconf/201814901014 SN - 2261-236X VL - 149 SP - 01014-1 EP - 01014-8 PB - EDP Sciences CY - Les Ulis AN - OPUS4-44433 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Leinitz, Sarah ED - Diouri, A. ED - Boukhari, A. ED - Ait Brahim, L. ED - Bahi, L. ED - N., Khachani ED - Saadi, M ED - Aride, J. ED - Nounah, A. T1 - Concrete casting robustness improvement due to active rheology N2 - With ongoing innovation in process technology, the challenges of concrete technology are more and more focused on the rheological optimisation for these processes, since improper mixture stability or poor compaction ability negatively affect the concrete homogeneity and quality. However, along with the increasing complexity of today’s concrete mixture compositions, concrete becomes more prone to failure regarding the casting process. Variable properties of the raw materials typically cause changing workability. The reasons can be found among others in scattering water contents, physical or chemical properties of the cement or varying environmental temperatures. Robustness in the delicately adjusted rheology, however, is of utmost importance for modern and future process technology, from sprayed concrete over pumpable concrete towards 3D-printing, with regard to the long-term strength, the function and the durability. Typically, material induced changes cannot be identified easily due to the complex interactions of concrete constituents. Therefore, a precise and prompt counteraction is impossible. However, it is known that the yield stress can be controlled by addition of supplementary superplasticizer or stabilising agent. In combination with computerized process observation tools that can rapidly interpret and react on changes in the rheology, it is therefore thinkable, that only these two admixture types can adjust the rheology steadily and permanently, regardless of the actual root cause for observed macroscopic rheology change. The presentation will firstly give a comprehensive overview of effects at the interface between pore solution, particles and hydrates, which affect the rheology of fresh concrete. Secondly, ways are recommended how the rheology can be actively manipulated before eventually computerized methods are demonstrated that help to actively and rapidly assess and counteract performance scatter during steady casting processes. T2 - 2nd International Congress on Materials & Structural Stability (CMSS-2017) CY - Rabat, Morocco DA - 22.11.2017 KW - Cusum KW - Rheology KW - Control Chart KW - Concrete KW - Robustness PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444317 DO - https://doi.org/10.1051/matecconf/201814901001 SN - 2261-236X VL - 149 SP - 01001-1 EP - 01001-7 PB - EDP Sciences CY - Les Ulis AN - OPUS4-44431 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shamsuddoha, Md A1 - Hüsken, Götz A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Baeßler, Matthias ED - Alexander, M.G. ED - Beushausen, H. ED - Dehn, F. ED - Moyo, P. T1 - Workability and mechanical properties of ultrafine cement based grout for structural rehabilitation: A parametric study on the partial replacement with SCMs N2 - Grouting is a universal repair and strengthening technique, which is constantly used for structural remediation of concrete components, trenches, mine subsidence, dam joints, restoration of masonry structures, and geological stabilizations. Having an extremely small particle size of only few microns, ultrafine cements are ideal for grouting applications due to their superior permeability and compressive strength properties of the hardened cement paste compared to that of the less-expensive, but coarser ordinary Portland cements. Supplementary cementitious materials (SCMs) are often used to replace ultrafine cement in order to modify certain properties and to reduce costs. The aim of this experimental study is to investigate the effect of three supplementary materials: microsilica (MS), fly ash (FA), and metakaolin (MK) on the workability, and mechanical properties of an ultrafine cement based grout with a constant water-binder ratio and constant superplasticizer content. Maximum percentages of replacement with ultrafine cement were 6% by volume of cement for MS and 16% for FA, and MK. In general, results suggest that the workability is improved by addition of FA, whereas is reduced, when modified with MS and MK. The compressive strength of grout after cement replacement remains comparable to that of pure cement grout. However, there is a tendency of the MS to positively affect the compressive strength opposite to FA, whereas flexural strength is positively affected by FA. Based on the results, it is evident that grouts with Hägerman cone flow more than 500 mm and compressive strength of more than 90 MPa after 28 days can be produced. T2 - International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) CY - Cape Town, South Africa DA - 19.11.2018 KW - Grouting KW - Repair KW - Box-Behnken KW - Supplementary cementitious materials KW - Analysis of variance PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464769 DO - https://doi.org/10.1051/matecconf/201819907006 SN - 2261-236X VL - 199 SP - 07006-1 EP - 07006-7 PB - MATEC Web of Conferences AN - OPUS4-46476 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Crasselt, Claudia T1 - Influence of rheology modifying admixtures on hydration of cementitious suspensions N2 - The state of fresh concrete is predominantly determined by the rheological properties of the cement paste. In order to control performance spectra and requirements of novel concretes and to better understand macroscopic phenomena, comprehensive knowledge of the material behavior of fresh cement suspensions as well as of the complex relationships of mechanisms at the nano and micro scale are necessary. This work focuses on micro and nano rheology of suspensions of cementitious model systems and the influence of polycarboxylate-based admixtures on the rheology. The phenomena are driven by multiple parameters such as adsorption and particle interactions. Hence, the first part examines the interaction between polycarboxylate ether (PCE) and synthesized clinker phases and hydration products as model systems with regard to early hydration products. T2 - 6th International Symposium on Nanotechnology in Construction CY - Hong Kong, China DA - 02.12.2018 KW - Cement KW - Early hydration KW - Polycarboxylate ether (PCE), PY - 2018 AN - OPUS4-46980 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Diehn, Sabrina A1 - Zimmermann, B. A1 - Bagcioglu, M. A1 - Seifert, Stephan A1 - Kohler, A. A1 - Ohlson, M. A1 - Fjellheim, S. A1 - Weidner, Steffen A1 - Kneipp, Janina T1 - Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) shows adaption of grass pollen composition N2 - MALDI time-of-flight mass spectrometry (MALDI-TOF MS) has become a widely used tool for the classification of biological samples. The complex chemical composition of pollen grains leads to highly specific, fingerprint-like mass spectra, with respect to the pollen species. Beyond the species-specific composition, the variances in pollen chemistry can be hierarchically structured, including the level of different populations, of environmental conditions or different genotypes. We demonstrate here the sensitivity of MALDI-TOF MS regarding the adaption of the chemical composition of three Poaceae (grass) pollen for different populations of parent plants by analyzing the mass spectra with partial least squares discriminant analysis (PLS-DA) and principal component analysis (PCA). Thereby, variances in species, population and specific growth conditions of the plants were observed simultaneously. In particular, the chemical pattern revealed by the MALDI spectra enabled discrimination of the different populations of one species. Specifically, the role of environmental changes and their effect on the pollen chemistry of three different grass species is discussed. Analysis of the Group formation within the respective populations showed a varying influence of plant genotype on the classification, depending on the species, and permits conclusions regarding the respective rigidity or plasticity towards environmental changes. KW - Pollen KW - MALDI-TOF MS KW - Classification KW - Partial least square discriminant analysis (PLS-DA) KW - Principal component analysis (PCA) PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465294 DO - https://doi.org/10.1038/s41598-018-34800-1 SN - 2045-2322 VL - 8 IS - 1 SP - 16591, 1 EP - 11 PB - Nature AN - OPUS4-46529 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schenderlein, Matthias T1 - Monitoring early stage corrosion processes during biofilm formation N2 - To investigate early stage corrosion processes of stainless steel 1.4301 taking place during the biofilm formation of the organism Shewanella putrefaciens electrochemical impedance spectroscopy (EIS) in a multielectrode approach has been used. The multielectrode array consisted of up to 25 electrically isolated electrodes made of stainless steel wires of diameters ranging from 100 µm to 500 µm. They were connected to a multichannel microelectrode analyzer (MMA) electrically coupled through zero resistance ammeters. Current flow between electrodes in the array as well as changes in impedance of individual electrodes over time were recorded and analyzed with respect to the onset of localized corrosion and biofilm formation. The results were complemented by optical microscopy, SEM and AFM images which were taken immediately after the respective experiment. To verify that the multielectrode arrays correctly indicated the initial stages of the corrosion process and of biofilm formation they were introduced in a flow cell reaction vessel containing test specimens made from stainless steel 1.4301, which were checked regularly for signs of localized corrosion and biofilms. Preceding results with the multielectrode array in solutions containing high amounts of chloride ions and hydrogen peroxide at low pH also showed that it is possible with the MMA to monitor individual electrodes becoming local anodes as local corrosion set in, while the remaining electrodes predominantly acted as cathodes. T2 - 69th Annual Meeting of the International Society of Electrochemistry CY - Bologna, Italy DA - 02.09.2018 KW - Corrosion KW - Multielectrode KW - Biofilm KW - Monitoring KW - Stainless steel PY - 2018 AN - OPUS4-47095 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Trimpin, S. A1 - Lee, C. A1 - Weidner, Steffen A1 - El-Baba, T. A1 - Lutomski, C. A1 - Inutan, E. A1 - Foley, C. A1 - Ni, C.-K. A1 - McEwen, C. T1 - Unprecedented Ionization Processes in Mass SpectrometryProvide Missing Link between ESI and MALDI N2 - In the field of mass spectrometry,producing intact, highly-charged protein ions from surfaces is a conundrum with significant potential payoff in application areas ranging from bio-medical to clinical research. Here, we report on the ability to form intact, highly-charged protein ions on high vacuum time-of-flight mass spectrometers in the linear and reflectron modes achievable using experimental conditions that allow effective matrix removal from both the sample surfaces and from the charged clusters formed by the laser Ablation event. The charge states are the highest reported on high vacuum mass spectrometers, yet they remain at only around athird of the highest charge obtained using laser ablation with a suitable matrix at atmospheric pressure. Other than physical instrument modifications, the key to forming abundant and stable highly-charged ions appears to be the volatility of the matrix used. Cumulative results suggest mechanistic links between the ionization process reported here and traditional ionization methods of electrospray ionization and matrix-assisted laser desorp-tion/ionization. KW - MALDI KW - Electrospray KW - Mass spectrometry KW - Ionization PY - 2018 DO - https://doi.org/10.1002/cphc.201701246 SN - 1439-4235 SN - 1439-7641 VL - 19 IS - 5 SP - 581 EP - 589 PB - Wiley-VCH AN - OPUS4-44404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - You, Zengchao T1 - Nanoparticles separation using capillary electrophoresis N2 - Nowadays, different nanoparticles have been developed for commercial applications. However, since data on toxicity are barely available, their increasing application in cosmetic products, food and their release in the environment might cause severe problems. An accurate separation, identification and characterization of nanoparticles becomes increasingly important. A common method for nanoparticle separation, which was introduced in 1976 by Giddings, represents asymmetrical field-flow fractionation (AF4). It is a flow based separation method, which can be theoretically used to separate particles range from 1 nm to 50 µm. However, when the particles are smaller than 10 nm, separation with AF4 will become difficult to perform. Because in this case strong separation force, which induces aggregation of particles, should be applied. This will decrease recoveries of analytes and limit its application in accurate quantitative analysis. Capillary electrophoresis (CE) is another well-developed separation technique, in which samples will be separated in relation to their electrophoretic mobility. In recent years, CE has been used to separate different kinds of nanoparticles like, gold colloids or CdSe Quantum dots. However, till now only separation of particles smaller than 50 nm was reported. Because large size distribution of bigger particles will result in strong peak broadening and long separation time. A two-dimensional coupling of AF4 and CE might provide us a new separation method, which can extend the separation ranges of both methods and be a way to characterise particles with large size distributions. T2 - ESAS-CANAS Konferenz CY - Berlin, Germany DA - 21.03.2018 KW - Nanoparticles separation capillary electrophoresis asymmetrcial flow field flow fractionation PY - 2018 AN - OPUS4-47188 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Günster, Jens A1 - Zocca, Andrea A1 - Lima, Pedro A1 - Acchar, W. T1 - 3D printing of porcelain by layerwise slurry deposition N2 - The Layerwise Slurry Deposition is a technology for the deposition of highly packed powder layers. A powder bed is achieved by depositing and drying layers of a ceramic suspension by means of a doctor blade. This deposition technique was combined with the binder jetting technology to develop a novel Additive Manufacturing technology, named LSD-print. The LSD-print was applied to a porcelain ceramic. It is shown that it was possible to produce parts with high definition, good surface finish and at the same time having physical and mechanical properties close to those of traditionally processed porcelain, e.g. by slip casting. This technology shows high future potential for being integrated alongside traditional production of porce-lain, as it is easily scalable to large areas while maintaining a good definition. Both the Layerwise Slurry Deposition method and the binder jetting technologies are readily scalable to areas as large as > 1 m2. KW - Binder jetting KW - Additive Manufacturing KW - 3D printing KW - Porcelain PY - 2018 DO - https://doi.org/10.1016/j.jeurceramsoc.2018.03.014 SN - 0955-2219 VL - 38 IS - 9 SP - 3395 EP - 3400 PB - Elsevier Ltd. AN - OPUS4-45713 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Piechotta, Christian T1 - Environmental sustainability and –stability of Materials concerning the Migration of pollutants N2 - MaUS is an acronym for ”Material und Umweltsimulationen“. Plastics are in the focus of environmental politics due to their long-term behaviour and therefore to their persistence. Not only that they appear as visible contaminants in the sea and on the beach, but their unknown behaviour concerning their additives as well as the related transformation products are anxious. Therefore, we wish to establish a certified reference method to provide a method for testing plastics. Aim of this project is the development of fast motion standard reference methods for testing plastics regarding to their environmental compatibility. To establish these testing methods, we use polystyrene (PS) and polypropylene (PP) with environmental relevant brominated flame retardants, known for their persistent bioaccumulative and toxic (PBT) properties. In case of PS the material contains 1 wt% of 1,2,5,6,9,10-hexabromocyclododecan (HBCD) and in case of PP 0.1 wt% bromodiphenylether (BDE-209), which is known as a substance of very high concern (SVHC). Furthermore, we use polycarbonate (PC), which is still used as material in baby flasks and releases Bisphenol A (BPA), an estrogenic active substance. As an additional material PTFE is used for its importance as a source for two ubiquitous environmental substances (PFOS and PFOA), whose toxicological effects are still incompletely known. The focus in this current work is set on the transfer of potential pollutants out of applied materials mentioned above into environmental compartments like water or soil. Here an accelerated aging concept should be developed to shortened time consuming natural processes. For these resulting simulations we use a programmable weathering chamber with dry and wet periods and with high and low temperatures. These programmes run for several weeks and according to a defined sampling schedule we take water samples, run a clean-up procedure by SPE (Molecular imprinted polymers (MiPs) resp. polymer-based cartridges (Waters Oasis HLB)) and analyse them by HPLC-UV resp. LC-MS/MS. Of most interest in case of flame retardants are photocatalytic transformation products. Therefore, we conduct a non-target-screening resp. a suspected target-screening by LC-MS/MS and HRMS. T2 - Project meeting PlasticsEurope - BAM CY - Leverkusen, Germany DA - 06.11.2018 KW - Environmental simulation KW - Pollutants PY - 2018 AN - OPUS4-47026 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bernardino, R. A1 - Wirth, C. A1 - Stares, S.L. A1 - Salmoria, G.V. A1 - Hotza, D. A1 - Günster, Jens T1 - Manufacturing of SiO2-Coated b-TCP Structures by 3D Printing using a Preceramic Polymer as Printing Binder and Silica Source N2 - Tricalcium phosphate (b-TCP) can be used as bone graft, exhibiting suitable bioabsorption and osteoconduction properties. The presence of silica may induce the formation of a hydroxyapatite layer, enhancing the integration between implant and bone tissue. Preceramic polymers present silicon in their composition, being a source of SiO2 after thermal treatment. Using the versatility of 3D printing, b-TCP and a polysiloxane were combined to manufacture a bulkb-TCP with a silica coating. For the additive manufacturing process, PMMA powder was used as passive binder for the b-TCP particles, and polymethylsilsesquioxane (MK), dissolved in an organic solvent, was used both as a printing binder (ink) and as the source of SiO2 for the coating. Five distinct coating compositions were printed with increasing amounts of MK. The structures were then submitted to heat treatment at 1180 °C for 4 h. XRD and FTIR showed no chemical reaction between the calcium phosphate and silica. SEM allowed observation of a silicon-based ating on the structure surface. Mechanical strength of the sintered porous structures was within the range of that of trabecular bones. KW - Tricalcium Phosphate KW - 3D-Printing KW - Preceramic polymer KW - Bone regeneration PY - 2018 DO - https://doi.org/10.4416/JCST2017-00056 VL - 9 IS - 1 SP - 37 EP - 41 PB - Göller Verlag CY - 76532 Baden-Baden AN - OPUS4-45715 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Kricheldorf, H. R. T1 - Spirocyclic bisphenoxides of Ge, Zr, and Sn as catalysts for ring-expansion polymerizations of L- and meso-lactide N2 - Spirocyclic phenoxides of germanium, zirconium, and tin were prepared from 2,20-dihydroxybiphenyl and 2,20-dihydroxy-1,10-binaphthyl. Ring-expansion polymerizations of L-lactide are mainly studied at 160 or 180 °C. The reactivity of the catalysts increases in the order: Zr < Ge < Sn. Regardless of catalyst, the weight-average molecular weights (Mw) never exceed 50,000 g mol−1. The resulting poly(L-lactide)s are optically pure and have a cyclic architecture. Decreasing temperature and time favor Formation of even-numbered cycles, and at 102 ° cyclics, almost free of odd-numbered rings are obtained. Analogous polymerizations of meso-lactide give similar results >120 °C, but different results at 100 or 80 °C. Surprisingly, bell-shaped narrow molecular weight distributions are obtained <140 °C, resembling the pattern of living polymerizations found for alcohol-initiated polymerizations. An unusual transesterification mechanism yielding narrow distributions of odd-numbered cycles is discovered too. KW - Cyclization KW - Polylactides KW - MALDI-TOF MS KW - Ring-opening polymerization KW - Spirocyclic PY - 2018 DO - https://doi.org/10.1002/pola.29259 SN - 0887-624X SN - 1099-0518 VL - 56 IS - 24 SP - 2730 EP - 2738 PB - Wiley Periodicals AN - OPUS4-46498 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koerdt, Andrea T1 - Microbial corrosion of iron coupled to methanogenesis by strains from different environments N2 - Microbially influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) which act upon the metal by the reactiveness of hydrogen sulfide, and by withdrawal of the available electrons in electrical contact with the metal. Methanogenic archaea are supposed to cause MIC. Because they do not produce hydrogen sulfide, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood. Precipitation of siderite (4Fe + 5HCO3 + 5H+  4FeCO3 + CH4 + 3H2O) can lead to an insulating layer on the metal surface and lower the corrosion rate. Still, the extent of FeCO3 precipitation may be significantly influenced by environmental conditions such as pH and advective processes. T2 - EMBO-Workshop CY - Vienna, Austria DA - 02.08.2018 KW - Methanogens KW - MIC KW - Corrosion KW - Environmental Simulation PY - 2018 AN - OPUS4-46396 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Agea Blanco, Boris A1 - Meyer, Christian A1 - Müller, Ralf A1 - Günster, Jens T1 - Sand erosion of solar glass: Specific energy uptake, total transmittance, and module efficiency N2 - Surface roughness, R Z , normal transmittance, Τ N , total transmittance, Τ T , and photovoltaic (PV) module efficiency, η S , were measured for commercial solar glass plates and PV test modules identically sandblasted with different loads of quartz sand (200 – 400 μ m), impact inclination angles, and sand particle speed. Measured data are presented versus the specific energy uptake during sand blasting, E (J/m2). Cracks, adhering particles, and scratch ‐ like textures probably caused by plastic flow phenomena could be observed after sand blasting. Their characteristic size was much smaller than that of sand particles. After blasting and subsequent cleaning, the glass surface was still covered with adhering glass particles. These particles, cracks, and scratch ‐ like textures could not be removed by cleaning. For sand blasting with α = 30° inclination angle and E = 30 000 J/m2, normal transmittance, total transmittance, and relative module efficiency decreased by 29%, 2% and ∽ 2%, respectively. This finding indicates that diffusive transmission of light substantially contributes to PV module efficiency and that the module efficiency decrease caused by sand erosion can be better estimated from total than by normal transmittance measurements. KW - Transmittance KW - Efficiency KW - Photovoltaic modules KW - Roughness KW - Sand blasting PY - 2018 DO - https://doi.org/10.1002/er.3930 SN - 1099-114X SN - 0363-907X VL - 42 IS - 3 SP - 1298 EP - 1307 PB - Wiley & Sons, Ltd. AN - OPUS4-44157 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bäßler, Ralph T1 - Rezension: Sicherer Umgang mit Gefahrstoffen N2 - Dieses Handbuch wird seinem Anspruch gerecht, anschaulich praxisbezogenes und zeitgemäßes Wissen über alle Gesetze und Verordnungen beim Umgang mit gefährlichen Stoffen in Ausbildung und Beruf zu bieten. Dass dies auch in einer für Nicht‐Juristen verständlichen Form geschieht, macht das Buch zu einem guten Nachschlagewerk und Leitfaden für den Nutzer. KW - Gefahrstoff PY - 2018 DO - https://doi.org/10.1002/maco.201870085 SN - 0947-5117 VL - 69 IS - 8 SP - 2 PB - Wiley‐VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-46747 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bäßler, Ralph T1 - Book review: Corrosion science and technology N2 - It can be concluded, that this book fulfills its intention to be a relevant practical guide for students and professionals. The interested reader can get an insight into of all kinds of aspects one should consider when dealing with corrosion. KW - Corrosion PY - 2018 DO - https://doi.org/10.1002 maco.201870114 SN - 0947-5117 VL - 69 IS - 11 SP - 1677 EP - 1678 PB - Wiley‐VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-46748 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Le, Quynh Hoa A1 - Bäßler, Ralph A1 - Knauer, S A1 - Kratzig, Andreas A1 - Bettge, Dirk A1 - Kranzmann, Axel T1 - Droplet corrosion of CO2 transport pipeline steels N2 - This work examined the droplet corrosion of CO2 pipeline steels caused by impurities in CO2 supercritical/dense phase at 278 K, simulating the underground transport condition. The wetting properties of carbon steels (X52 and X70) as well as martensitic steel UNS S41500, and superaustenite UNS N08031 were studied by contact angle measurement, revealing reactive wetting behavior of carbon steels. Exposure tests with CO2 saturated water droplet on steel surface showed that the impurities (220 ppmv SO2 and 6700 ppmv O2) diffused into the droplet and then reacted with metal coupons in supercritical/dense phase condition, forming the corrosion product instantly during pumping process. Due to the active wetting behavior, the carbon steels suffered from heavily attack, while negligible corrosion product was observed in cases of martensitic steel UNS S41500 and superaustenite UNS 08031 coupons. Condensation experiments that were carried out on fresh polished coupons in CO2 with 1200 ppmv H2O showed that the formation and aggregation of droplet is dependent on the presence of impurities. Without SO2 and O2, the same concentration of H2O did not cause observable corrosion process after a week of exposure. With 220 ppmv SO2 and 6700 ppmv O2 even low water concentration (5-30 ppmv) still resulted in heterogeneous nucleation and subsequent growth of droplets, leading to corrosive process on carbon steel surface albeit to a lesser extent. T2 - CORROSION 2018 CY - Phoenix, AZ, USA DA - 15.04.2018 KW - CCUS KW - Supercritical/dense phase CO2 KW - Carbon steels KW - Martensitic steel KW - Superaustenite steel KW - Droplet corrosion PY - 2018 SP - Paper 10845, 1 EP - 11 PB - NACE International Publications Division CY - Houston, Texas, USA AN - OPUS4-44798 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Torge, Manfred T1 - Analytische Untersuchungen an Glasmalfarben mittels EDX und LIBS N2 - Nach 1850 wurde zur weiteren Herabsetzung der Einbrenntemperatur von Glasmalfarben Borax (Na2B4O7 · 10 H2O) zugesetzt. Das Verhältnis war nun 1 Teil SiO2, 3 Teile PbO und 0,5 Teile Borax. Der analytische Nachweis von Bor in eingebrannten Malschichten war bisher jedoch nicht möglich. In Laborversuchen wurden Glasmalfarben mit unterschiedlichem Gehalt an Borax auf Modellgläser aufgetragen, eingebrannt und anschließend unter simulierten Umweltbedingungen zeitraffend im Klimaschrank bewittert. Mit Hilfe von elektronenmikroskopischen Untersuchungen können Malschichten charakterisiert werden und somit Hinweise auf mögliche Schadensursachen liefern. Der Nachweis von Bor erfolgte mit Hilfe von LIBS-Messungen (Laser Induced Breakdown Spectroscopy) an im Labor hergestellten Glasmalfarben mit unterschiedlichem Boraxgehalt. T2 - Archäometrie und Denkmalpflege 2018 CY - Hamburg, Germany DA - 20.04.2018 KW - Glasmalfarben KW - Umweltsimulation KW - Analytik PY - 2018 AN - OPUS4-45069 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Özcan Sandikcioglu, Özlem T1 - Changes in passive film chemistry of stainless steels in the presence of iron reducing bacteria N2 - Summary of the results obtained at DELTA-Beamline 8 in 2018. T2 - DELTA User Treffen CY - Dortmund, Germany DA - 28.11.2018 KW - MIC KW - Corrosion KW - XANES PY - 2018 AN - OPUS4-50312 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Kricheldorf, H. T1 - Transesterification in alcohol-initiated ROPs of l- and meso-lactide catalyzed by Sn(II) and Sn(IV) compounds at low temperatures N2 - The purpose of this study is to shed more light on the transesterification processes in alcohol-initiated and tin(II) 2-ethylhexanoate (SnOct2)-catalyzed polymerizations of lactides at low or moderate temperatures. Ethanol-initiated polymerizations are conducted in concentrated solutions at 80 °C and a strong dependence of even/odd equilibration on the alcohol/Sn ratio. Around or above 120 °C cyclization of poly(l-lactide) via “backbiting” occurs as a third mechanism. However, poly(m-lactide) shows a higher cyclization tendency and yields cyclics even at 100 °C. Combinations of ethanol and certain cyclic dibutyltin(IV) catalysts also yield cyclic oligomers of l-lactide at 80 °C. Reaction conditions allowing for a total suppression of all transesterification reactions are not found, but even-numbered poly(m-lactide)s with a purity >95% are obtained at 70 or 60 °C. KW - Cyclization KW - MALDI-TOF MS KW - Polyester KW - Polylactide KW - Transesterification PY - 2018 DO - https://doi.org/10.1002/macp.201800445 SN - 1022-1352 SN - 1521-3935 VL - 219 IS - 24 SP - 1800445, 1 EP - 10 PB - Wiley-VCH CY - Weinheim AN - OPUS4-46705 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Aristia, Gabriela A1 - Bäßler, Ralph A1 - Roth, C. T1 - Polyaniline/silicon dioxide containing coating for use in artificial geothermal brines N2 - Geothermal brine is a complex system containing a wide variety of dissolved salts resulting from the condition s in a geothermal well. These fluids lead to corrosion in pipes and other parts of geothermal system construction and necessitate intense research efforts in finding new suitable materials. Carbon steel is susceptible to corrosion in geothermal brine especially when it is exposed to a high temperature and high-pressure medium, which is considered to be an aggressive environment. An artificial geothermal water, bas ed on a brine composition found in Indonesia, was used to investigate the performance of high alloyed materials. The electrolyte has pH 4 and contains 1,500 mg/l Cl-, 20 mg/l SO4 2-, 15 mg/l HCO3 -, 200 mg/l Ca 2+, 250 mg/l K+, and 600 mg/l Na+. In order to protect the bare material in geothermal application, it is necessary to either use high alloyed material s or coatings. In this research, a coating system consisting of polyaniline and silicon dioxide was investigated regarding its behavior to protect carbon steel. In detail, the effect of SiO2 and polyaniline (PANi) addition was evaluated by exposure and electrochemical tests for 7 days, i.e. electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP ) at room temperature and 150 °C with 1 MPa pressure . T2 - NACE International Annual Corrosion Conference CY - Phoenix, AZ, USA DA - 15.04.2018 KW - Geothermal KW - Coating KW - SiO 2 KW - Polyaniline KW - Corrosion PY - 2018 SP - 10708, 1 EP - 14 PB - Omnipress CY - Houston AN - OPUS4-44916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Torge, Manfred T1 - EDX-Untersuchungen an mittelaltelichen Gläsern und innovativer Schutz der Glasmalereien N2 - In Vorbereitung einer Restaurierung erfolgten naturwissenschaftliche Untersuchungen zu Schadensphänomenen und Glaszusammensetzungen an mittelalterlichen Gläsern aus der Dorfkirche in Koszewko (Polen)im Environmental Scanning Electron Microscope (ESEM) mit EDX. Die Ergebnisse zeigen, dass die Glasverwitterung schon sehr stark vorangeschritten ist und ein zukünftiger Schutz der mittelalterlichen Glasmalereifelder vor Umwelteinflüssen unbedingt notwendig ist. Es wurde ein Schutzverglasungsystem entwickelt, das speziell auf den langfristigen Erhalt der einzelnen mittelalterlichen Glasmalereifelder ausgelegt ist. T2 - 21th Congress of Association Internationale pour l´Histoire du Verre CY - Istanbul, Turkey DA - 03.09.2018 KW - Glasanalyse KW - ESEM KW - Schutzverglasung PY - 2018 AN - OPUS4-45947 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stock, S. C. A1 - Köster, M. A1 - Dippold, M. A. A1 - Nájera, F. A1 - Matus, F. A1 - Merino, C. A1 - Boy, J. A1 - Spielvogel, S. A1 - Gorbushina, Anna A1 - Kuzyakov, Y. T1 - Environmental drivers and stoichiometric constraints on enzyme activities in soils from rhizosphere to continental scale N2 - Microbial activity and functioning in soils are strongly limited by carbon (C) availability, of which a great proportion is released by living roots. Rhizodeposition and especially root exudates stimulate microbial activity and growth, and may shift the stoichiometric balance between C, N, and P. Thereby, exudates heighten microbial nutrient demand and acquisition of N and P from organic matter, leading to an increase in enzyme production. Aim of this study was to determine environmental controls of extracellular enzyme production, and hence on potential enzyme activities (Vmax) and substrate affinities (Km). To determine the controlling factors, we worked on four spatial scales from the microscale (i.e. rhizosphere) through the mesoscale (i.e. soil depth) and landscape scale (relief positions), and finally to the continental scale (1200 km transect within the Coastal Cordillera of Chile). Kinetics of seven hydrolyzing enzymes of the C, N, and P cycles (cellobiohydrolase, β‑glucosidase, β‑xylosidase, β‑N‑acetylglucosaminidase, leucine‑aminopeptidase, tyrosine‑aminopeptidase, and acid phosphatase) were related to soil texture, C and N contents, pH, and soil moisture via redundancy analysis (RDA). Potential activities of C, N, and P acquiring enzymes increased up to 7-times on the continental scale with rising humidity of sites and C and N contents, while substrate affinities simultaneously declined. On the landscape scale, neither Vmax nor Km of any enzyme differed between north and south slopes. From top- to subsoil (down to 120 cm depth) potential activities decreased (strongest of aminopeptidases under humid temperate conditions with up to 90%). Substrate affinities, however, increased with soil depth only for N and P acquiring enzymes. Affinities of cellobiohydrolase and β‑xylosidase, on the contrary, were 1.5- to 3-times higher in top- than in subsoil. Potential activities of N and P acquiring enzymes and β‑glucosidase increased form bulk to roots. Simultaneously, substrate affinities of N and P acquiring enzymes declined, whereas affinities of β‑glucosidase increased. These trends of activities and affinities in the rhizosphere were significant only for acid phosphatase. The RDA displayed a strong relation of potential activities of C and P acquiring enzymes and β‑N‑acetylglucosaminidase to C and N contents in soil as well as to the silt and clay contents. Aminopeptidase activity was mainly dependent on soil moisture and pH. We conclude that substrate availability for microorganisms mainly determined enzyme activity patterns on the continental scale by the humidity gradient. Patterns on the meso- and microscale are primarily controlled by nutrient limitation, which is induced by a shift of the stoichiometric balance due to input of easily available C by roots in the rhizosphere. KW - Extracellular enzymes KW - Stoichiometric homeostasis KW - Rhizosphere effect KW - Nutrient acquisition KW - Multi-scale study PY - 2018 DO - https://doi.org/10.1016/j.geoderma.2018.10.030 SN - 0016-7061 SN - 1872-6259 VL - 2019 IS - 337 SP - 973 EP - 982 PB - Elsevier B.V. AN - OPUS4-46829 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witt, Julia T1 - In situ AFM studies of deformation and corrosion processes on AA2024-T3 aluminium alloy N2 - The performance of functional coatings and adhesively joined hybrid components relies strongly on the stability of the polymer-metal interface. With the increasing utilization of multi-material structures in the automotive and aerospace industry, it is of great scientific and technical interest to understand the processes leading to interface degradation and to develop novel strategies to increase corrosion and delamination resistance. The aim of this project is to develop thin epoxy-based films on aluminium alloy AA2024-T3 as a model system and to investigate their interfacial stability under corrosive and coupled corrosive-mechanical load. Electrochemical and spectroscopic methods were used for the characterisation of the film properties and in situ corrosion experiments were performed by means of AFM. The deformation properties of the aluminium alloy and the model coatings were investigated by means of scanning Kelvin probe force microscopy (SKPFM) utilizing the integrated tensile stage. The presentation will give a brief overview of the capabilities of the new AFM setup to foster future collaborations and summarize our work on the interface stability of model coatings. T2 - Abteilungskolloquium FB6 CY - Berlin, Germany DA - 27.11.2018 KW - Corrosion KW - In situ Atomic Force Microscopy (AFM) KW - Aluminium alloy KW - Scanning Kelvin Probe Force Microscopy (SKPFM) PY - 2018 AN - OPUS4-48027 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lee, Jun-Seob A1 - Radnik, Jörg A1 - Bäßler, Ralph T1 - Electrochemical behavior of UNS N08031 in Green-Death-solution N2 - The electrochemical behavior of UNS(1) N08031 was investigated as a function of electrode potential in Green-Death(2) solution at 40 °C. The UNS N08031 surface is in a stable passive state during cyclic potentiodynamic polarization without an initiation and/or propagation of localized corrosion. In potentiostatic polarization of UNS N08031 for 3600 s, passive current density increases with an increase in the passivation potential from 0.7 to 1.0 VSSE (silver/silver chloride reference electrode in saturated potassium chloride) Electrochemical impedance spectroscopy (EIS) and Mott-Schottky (M-S) analysis showed that a more defective n-type semiconductive passive film forms as the potential increases. X-ray photoelectron spectroscopy (XPS) revealed that passive film consists of mainly chromium and minor iron and nickel oxides. The mechanism of the defective passive film formation is discussed. The increase of the applied potential is considered to be a reason for the change in passive film stability. T2 - NACE International Annual Corrosion Conference CY - Phoenix, AZ, USA DA - 15.04.2018 KW - Steel KW - Passive film KW - X-ray photoelectron spectroscopy PY - 2018 SP - 10631, 1 EP - 9 PB - Omnipress CY - Houston AN - OPUS4-44915 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Le, Quynh Hoa A1 - Bäßler, Ralph A1 - Peetz, Christoph A1 - Buggisch, Enrico A1 - Bettge, Dirk A1 - Kranzmann, Axel T1 - Electrochemical study on wellbore constellations for CO2 injection N2 - Carbon Capture and Storage (CCS) is identified as an excellent technology to reach the target of CO2 reduction. However, the safety issue and cost effectiveness hinder the future of CCS. For the reliability and safety issues of injection wells the corrosion resistance of the materials used needs to be determined. In this study, representative low cost materials including carbon steel 1.8977 and low alloyed steel 1.7225 were embedded in cement to mimic the realistic casing-cement interface. Electrochemical studies were carried out using these metal-cement specimens in comparison with those made of metal only in CO2 saturated synthetic aquifer fluid, at 333 K, to reveal the effect of cement on the steel performance. The results showed the protective effect of cement on the performance of pipeline metals during polarisation process. However, the corrosion current density was high in all cases, with and without cement, indicating that the corrosion resistance of these materials is low. This conclusion was supported by the surface analysis of the polarized specimens, which revealed both homogenous and pitting corrosions. T2 - EUROCORR 2018 CY - Krakow, Poland DA - 09.09.2018 KW - CCUS KW - Supercritical/dense phase CO2 KW - Carbon steels KW - Martensitic steel KW - Superaustenite steel KW - Injection KW - Impurities PY - 2018 SP - 1 EP - 4 PB - EFC CY - Krakau, Poland AN - OPUS4-46291 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Regenspurg, S. T1 - Lessons learned from long-term corrosion investigations and –monitoring in saline thermal waters N2 - Investigations of corrosion processes in geothermal well in Groß Schönebeck showed Most tested materials (apart of carbon steel) proved to be corrosion resistant within the installations. - Stability of coatings cannot be guaranteed. - Main risk: Electrochemical corrosion of carbon steel casing with dissolved Cu resulting in clogging the reservoir The corrosion prevention strategy requires use of higher alloyed casing materials depending on resistance parameters, availability and economic feasibility. T2 - Der Geothermiekongress 2018 CY - Essen, Germany DA - 27.11.2018 KW - Geothermal KW - Corrosion KW - Stainless steel KW - Electrochemistry PY - 2018 UR - http://www.der-geothermiekongress.de/tagungsband/fa9jDmTEjs3rSNq/ AN - OPUS4-46901 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tan, K. H. A1 - Sattari, S. A1 - Donskyi, Ievgen A1 - Cuellar-Camacho, J. L. A1 - Cheng, C. A1 - Schwibbert, Karin A1 - Lippitz, Andreas A1 - Unger, Wolfgang A1 - Gorbushina, Anna A1 - Adeli, M. A1 - Haag, R. T1 - Functionalized 2D nanomaterials with switchable binding to investigate graphene–bacteria interactions N2 - Graphene and its derivatives have recently attracted much attention for sensing and deactivating pathogens. However, the mechanism of multivalent interactions at the graphene–pathogen interface is not fully understood. Since different physicochemical parameters of graphene play a role at this interface, control over graphene’s structure is necessary to study the mechanism of these interactions. In this work, different graphene derivatives and also zwitterionic graphene nanomaterials (ZGNMs) were synthesized with defined exposure, in terms of polymer coverage and functionality, and isoelectric points. Then, the switchable interactions of these nanomaterials with E. coli and Bacillus cereus were investigated to study the validity of the generally proposed “trapping” and “nano-knives” mechanisms for inactivating bacteria by graphene derivatives. It was found that the antibacterial activity of graphene derivatives strongly depends on the accessible area, i.e. edges and basal plane of sheets and tightness of their agglomerations. Our data clearly confirm the authenticity of “trapping” and “nano-knives” mechanisms for the antibacterial activity of graphene sheets. KW - XPS KW - Graphene KW - Graphene–bacteria interaction PY - 2018 DO - https://doi.org/10.1039/c8nr01347k SN - 2040-3364 SN - 2040-3372 VL - 10 IS - 20 SP - 9525 EP - 9537 PB - RSC CY - London AN - OPUS4-45084 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lüchtenborg, Jörg T1 - Additive Manufacturing of Dense Ceramics with Laser Induced Slip Casting (LIS) N2 - Most additive manufacturing processes which produce dense ceramics are nowadays limited in size because of inevitable post-processing steps like for example binder removal in stereolithography. The additive manufacturing of voluminous ceramic parts is realized by powder bed based processes which, however, generate parts with residual porosity. Via infiltration these parts can be processed to dense parts like for example SiC but this is not possible for all ceramics like for example Si3N4. There is a lack of methods for the additive manufacturing of dense voluminous parts for most ceramics. We have developed a new additive manufacturing technology, the Laser Induced Slip casting (LIS), based on the layerwise deposition of slurries and their local drying by laser radiation. Laser Induced Slip casting generates ceramic green bodies which can be sintered to dense ceramic components like traditional formed ceramic powder compacts. We will introduce the LIS technology, green bodies and sintered parts will be shown and their microstructure and mechanical properties will be discussed. T2 - CIMTEC 2018 14th Ceramics Congress CY - Perugia, Italy DA - 04.06.2018 KW - Additive Manufacturing PY - 2018 AN - OPUS4-45781 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Le, Quynh Hoa T1 - Droplet corrosion of CO2 transport pipeline steels N2 - In this work, the focus was set on the corrosion process of condensate as drops on the surface of carbon steels (X52, X70), martensitic steel UNS S41500, and superaustenite UNS 08031 in CO2 atmosphere with impurities at 278 K (to simulate the transportation condition in a buried pipeline). Exposure tests were performed at both normal pressure and high pressure where CO2 is supercritical or in dense phase. The drop, 1 ‑ 10 µL in volume, was prepared by dropping CO2 saturated ultra-pure water onto the surface of steel coupons in a one-liter-autoclave. The CO2 gas stream, simulating the oxyfuel flue gas with varying concentration of impurities (SO2 and O2), was then pumped into the autoclave to observe the condensation and corrosion impacts of impurities. Comparable exposure tests were carried out with the same gas mixture and the same volume of water as vapor to observe the drop formation and the corrosion process that follows. The wettability and stability of drops on the surface of steel coupons in CO2 supercritical/dense phase environment was evaluated additionally by contact angle measurement. T2 - NACE 2018 CY - Phoenix, Arizona, USA DA - 15.04.2018 KW - Droplet corrosion KW - CCUS KW - Supercritical/dense phase CO2 KW - Carbon steels KW - Martensitic steel KW - Superaustenite steel PY - 2018 AN - OPUS4-44767 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sanchez-Martin, Pedro A1 - Becker, Roland A1 - Toepel, J. A1 - Gorbushina, Anna T1 - An improved test for the evaluation of hydrocarbon degradation capacities of diesel-contaminating microorganisms N2 - The development of a test to evaluate the degradation of semi-volatile fuels as diesel by microorganisms is presented. This method is based on the principles described in the CEC-L-103 Standard procedure that is exclusively meant for testing the biodegradability of non-volatile lubricants. Therefore, significant modifications involve aseptic conditions for testing specific microorganisms and conducting the test in closed vessels avoiding evaporation losses, while fuel quantification using gas chromatography-flame ionization detection (GC-FID) is retained. It is suggested that the modified procedure should enable routine application for semi-volatile hydrocarbon-based fuels. GC-FID provides additionally valuable information on the alteration of fuel component patterns during biodegradation. The procedure was successfully tested using two bacteria (Pseudomonas aeruginosa and Sphingomonas sp.) and two yeasts (Moesziomyces sp. and Candida sp.) isolated from real diesel contamination cases. All tested microorganisms caused a significant degradation of diesel fuel achieving hydrocarbon degradation percentages ranging from 23% to 35%. Specific aspects on the test modification and prospects for further modification regarding targeted investigations in the field of fuel contamination by microorganisms are briefly discussed. KW - Biofouling KW - Bacteria KW - Fungi KW - CEC-L-103 KW - GC-FID KW - Reference organisms PY - 2018 DO - https://doi.org/10.1016/j.ibiod.2018.01.009 SN - 0964-8305 VL - 129 SP - 89 EP - 94 PB - Elsevier AN - OPUS4-44524 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martin-Sanchez, Pedro Maria A1 - Gebhardt, Christopher A1 - Toepel, Jörg A1 - Barry, J. A1 - Munzke, N. A1 - Günster, Jens A1 - Gorbushina, Anna T1 - Monitoring microbial soiling in photovoltaic systems: A qPCR-based approach N2 - Soiling of photovoltaic (PV) systems compromises their performance causing a significant power loss and demanding periodical cleaning actions. This phenomenon raises great concerns in the solar energy field, thus leading to notable research efforts over the last decades. Soiling is caused by a dual action of dust deposition and biofouling. However, surprisingly, the microbiological contribution to PV soiling is often overlooked or underestimated. In this study, a variety of qPCR-based methods have been developed to quantify the microbial load of fungi, bacteria and phototrophs on PV panels. These protocols were evaluated by comparison with culturedependent methods, and were implemented with real solar plants for two years. The results show that the developed molecular methods are highly sensitive and reliable to monitor the microbial component of the soiling. Fungal biomass was clearly dominant in all analysed PV modules, while bacteria and phototrophs showed much lower abundance. Light microscopy and qPCR results revealed that melanised microcolonial fungi and phototrophs are the main biofilm-forming microorganisms on the studied solar panels. In particular, the fungal qPCR protocol is proposed as a useful tool for monitoring of PV soiling, and investigating the microbial contribution to specific soiling cases. KW - Solar panels KW - PV modules KW - Real-time qPCR KW - Bacteria KW - Fungi KW - Phototrophs PY - 2018 DO - https://doi.org/10.1016/j.ibiod.2017.12.008 SN - 0964-8305 VL - 129 SP - 13 EP - 22 PB - Elsevier Science AN - OPUS4-43892 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zocca, Andrea T1 - LSD- 3D printing: Powder based Additive Manufacturing, from porcelain to technical ceramics N2 - Powder based Additive Manufacturing (AM) processes are widely used for metallic and polymeric materials, but rarely commercially used for ceramic materials, especially for technical ceramics. This seemingly contradicting observation is explained by the fact that in powder based AM, a dry flowable powder needs to be used. Technical ceramics powders are in fact typically very fine and poorly flowable, which makes them not suitable for AM. The layerwise slurry deposition (LSD) is an innovative process for the deposition of powder layers with a high packing density for powder based AM. In the LSD process, a ceramic slurry is deposited to form thin powder layers, rather than using a dry powder This allows the use of fine powders and achieves high packing density (55-60%) in the layers after drying. When coupled with a printing head or with a laser source, the LSD enables novel AM technologies which are similar to *Denotes Presenter 42nd International Conference & Exposition on Advanced Ceramics & Composites 127 Abstracts the 3D printing or selective laser sintering, but taking advantage of having a highly dense powder bed. The LSD -3D printing, in particular, offers the potential of producing large (> 100 mm) and high quality ceramic parts, with microstructure and properties similar to traditional processing. This presentation will give an overview of the milestones in the development of this technology, with focus on the latest results applied both to silicate and to technical ceramics. T2 - 42nd International Conference & Exposition on Advanced Ceramics and Composites CY - Daytona, FL, USA DA - 21.01.2018 KW - Additive Manufacturing KW - 3D printing KW - Ceramic KW - Alumina KW - Porcelain KW - Silicon Carbide PY - 2018 AN - OPUS4-44017 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lee, Jun-Seob A1 - Bäßler, Ralph T1 - Aging of passive film on UNS N08031 in a Green-Death solution N2 - Aging of passive film formed on UNS N08031 was investigated as a function of passivation time in Green-Death solution at 40°C. The specimen surface was in a stable passive state in the solution. The passive current density increased with an increase in the passivation potential. Electrochemical Impedance Spectroscopy and Mott–Schottky (M–S) analyses revealed that a more defective n-type semiconductive passive film formed as the potential increased while the film became stable as the defects in the film decreased at potential lower than 1.0 VSSE. The increase of the applied potential and the polarisation time are likely reasons for the change in passive film stability. KW - Iron–chromium–nickel alloy KW - Passivity KW - Green-Death solution KW - Flue gas desulphurisation facilities KW - Alloy 31 KW - Semiconductive layer PY - 2018 DO - https://doi.org/10.1080/1478422X.2018.1459077 SN - 1743-2782 SN - 1478-422X VL - 53 IS - 4 SP - 302 EP - 308 PB - Taylor & Francis AN - OPUS4-44923 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bäßler, Ralph T1 - Electrochemical behavior of UNS N08031 in Green-Death-solution N2 - The electrochemical behavior of UNS N08031 was investigated as a function of electrode potential in Green-Death solution at 40 °C. The UNS N08031 surface is in a stable passive state during cyclic potentiodynamic polarization without an initiation and/or propagation of localized corrosion. In potentiostatic polarization of UNS N08031 for 3600 s, passive current density increases with an increase in the passivation potential from 0.7 to 1.0 VSSE (silver/silver chloride reference electrode in saturated potassium chloride) Electrochemical impedance spectroscopy (EIS) and Mott-Schottky (M-S) analysis showed that a more defective n-type semiconductive passive film forms as the potential increases. X-ray photoelectron spectroscopy (XPS) revealed that passive film consists of mainly chromium and minor iron and nickel oxides. The mechanism of the defective passive film formation is discussed. The increase of the applied potential is considered to be a reason for the change in passive film stability. T2 - NACE International Annual Corrosion Conference CY - Phoenix, AZ, USA DA - 15.04.2018 KW - Steel KW - Passive film KW - X-ray photoelectron spectroscopy PY - 2018 AN - OPUS4-44920 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Aristia, Gabriela T1 - Polyaniline/silicon dioxide containing coating for use in artificial geothermal brines N2 - Geothermal brine is a complex system containing a wide variety of dissolved salts resulting from the condition s in a geothermal well. These fluids lead to corrosion in pipes and other parts of geothermal system construction and necessitate intense research efforts in finding new suitable materials. Carbon steel is susceptible to corrosion in geothermal brine especially when it is exposed to a high temperature and high-pressure medium, which is considered to be an aggressive environment. An artificial geothermal water, bas ed on a brine composition found in Indonesia, was used to investigate the performance of high alloyed materials. The electrolyte has pH 4 and contains 1,500 mg/l Cl-, 20 mg/l SO4 2-, 15 mg/l HCO3 -, 200 mg/l Ca 2+, 250 mg/l K+, and 600 mg/l Na+. In order to protect the bare material in geothermal application, it is necessary to either use high alloyed material s or coatings. In this research, a coating system consisting of polyaniline and silicon dioxide was investigated regarding its behavior to protect carbon steel. In detail, the effect of SiO2 and polyaniline (PANi) addition was evaluated by exposure and electrochemical tests for 7 days, i.e. electrochemical impedance spectroscopy (EIS) and open circuit potential (OCP) at room temperature and 150 °C with 1 MPa pressure. T2 - NACE International Annual Corrosion Conference CY - Phoenix, AZ, USA DA - 15.04.2018 KW - Geothermal KW - Coating KW - SiO2 KW - Polyaniline KW - Corrosion PY - 2018 AN - OPUS4-44919 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen T1 - Cyclic polylactides via ring-expansion polymerization N2 - We will report on a new kind of ring-expansion polymerization (REP) of cyclic esters based of three classes of catalysts. In contrast to REP described previously these new polymerizations are characterized by a self-extrusion of the catalysts resulting in cyclic homopolyesters as the only reaction product. These REP of L-lactide were performed in bulk at temperatures between 100 and 180°C without racemization. A simplified scheme of a REP catalyzed by BuCa or SnBi is presented below. With meso-lactide temperatures down to 60°C were realized. Depending on catalyst, time and temperature with equal quantities of even and odd-numbered cycles a strong predominance of either even or odd-numbered cycles was found. T2 - 255th ACS National Meeting CY - New Orleans, LA, USA DA - 18.03.2018 KW - MALDI-TOF MS KW - Poly(lactide) KW - Polymerisation KW - Catalysts PY - 2018 AN - OPUS4-44833 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen T1 - MALDI-TOF-MS for the determination of polymerization mechanisms of biodegradable polymers N2 - Eine neue Art einer Ring-Expansion Polymerization (REP) von zyklischen Polylaktiden mittels neuer Katalysatoren wird präsentiert. MALDI-TOF Massenspektrometrie und andere analytische Techniken wurden zur Aufklärung des Mechanismus eingesetzt. Dabei zeigte sich, dass im Gegensatz zu anderen REP, ausschließlich zyklische Polymere gebildet wurden. Diese stellen neue Kandidatenmaterialien für zukünftige neue CRM dar. T2 - 22. MALDI-Kolloquium CY - Berlin, Germany DA - 15.05.2018 KW - MALDI-TOF MS KW - Polylaktid KW - Zyklen PY - 2018 AN - OPUS4-44835 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Saadeh, Qais A1 - Pauw, Brian Richard A1 - Thünemann, Andreas T1 - In-situ SAXS techniques N2 - This project studies the orientation of nanoparticles under the influence of external stimuli such as electric fields, magnetic fields and ultra-sonic vibrations. A set of functional sample holders that fit inside the sample chamber of a state-of-the-art Small Angle X-ray Scattering (SAXS) machine, called the “Multi-scale Analyzer for Ultrafine Structures” (MAUS). The MAUS has been custom engineered to serve as a miniaturized Synchrotron, thus enabling standard material to be characterized to a high standard. Our work is needed to detail the fine characterization of reference nano-particles, not only on the nano-scale, but also coupled with external agents. A second aim of this project is to verify a few proof-of-concept designs for the alignment of nano-particles. Where the alignment of nano-particles In-Situ is intended to further develop 3D printing technologies, and SAXS is an ideal choice to study the alignment of an oriented ensemble. For more information about the MAUS; https://www.bam.de/Content/DE/Pressemitteilungen/2018/AnalyticalSciences/2018-01-31-mit-maus-an-die-spitze-der-nano-forschung.html T2 - NanoWorkshop 2018 (Workshop on Reference Nanomaterials. Current situation and needs: development, measurement, standardization) CY - Berlin, Germany DA - 14.05.2018 KW - SAXS KW - Nano-particles alignment KW - Magnetic nano-particles PY - 2018 AN - OPUS4-44912 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lauer, Franziska T1 - A graphical user interface for a fast multivariate classification of MALDI-TOF MS data of pollen grains N2 - The common characterization and identification of pollen is a time-consuming task that mainly relies on microscopic determination of the genus-specific pollen morphology. A variety of spectroscopic and spectrometric approaches have been proposed to develop a fast and reliable pollen identification using specific molecular information. Amongst them, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) shows a high potential for the successful investigation of such complex biological samples. Based on optimized MALDI sample preparation using conductive carbon tape, the application of multivariate statistics (e.g. principal components analysis, PCA) yields an enormous improvement concerning taxonomic classification of pollen species compared to common microscopic techniques. Since multivariate evaluation of the recorded mass spectra is of vital importance for classification, it’s helpful to implement the applied sequence of standard Matlab functions into a graphical user interface (GUI). In this presentation, a stand-alone application (GUI) is shown, which provides multiple functions to perform fast multivariate analysis on multiple datasets. The use of a GUI enables a first overview on the measured dataset, conducts spectral pretreatment and can give classification information based on HCA and PCA evaluation. Moreover, it can be used to improve fast spectral classification and supports the development of a simple routine method to identify pollen based on mass spectrometry. T2 - 12. Interdisziplinäres Doktorandenseminar, GDCh AK Prozessanalytik CY - BAM, AH, Berlin, Germany DA - 25.03.2018 KW - MALDI KW - GUI KW - Pollen PY - 2018 AN - OPUS4-44661 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lüchtenborg, Jörg T1 - Additive Manufacturing of Dense Ceramics with Laser Induced Slip Casting (LIS) N2 - The possibility to produce dense monolithic ceramic parts with additive manufacturing is at the moment restricted to small parts with low wall thickness. Up to now, the additive manufacturing of voluminous ceramic parts is realized by powder bed based processes which, however, generate parts with residual porosity. Via infiltration these parts can be processed to dense parts like for example SiC but this is not possible for all ceramics like for example Si3N4. There is a lack of methods for the additive manufacturing of dense voluminous parts for most ceramics. We have developed a new additive manufacturing technology, the Laser Induced Slip casting (LIS), based on the layerwise deposition of slurries and their local drying by laser radiation. Laser Induced Slip casting generates ceramic green bodies which can be sintered to dense ceramic components like traditional formed ceramic powder compacts. We will introduce the LIS technology, green bodies and sintered parts will be shown and their microstructure and mechanical properties will be discussed. T2 - 42nd International Conference and Expo on Advanced Ceramics and Composites CY - Daytona Beach, FL, USA DA - 21.01.2018 KW - Additive Manufacturing KW - Ceramics PY - 2018 AN - OPUS4-44182 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Aristia, Gabriela T1 - Electrochemical study of polyaniline/silicon dioxide containing coatings in geothermal solution N2 - Polyaniline/Silicon Dioxide containing coatings were electrochemically investigated in a saline geothermal solution. With the increase of exposure time, impedance values of coated specimens decreased at low frequency, which could be caused by the decrease of pore resistance due to electrolyte or water uptake. Coating system needs further optimization work. T2 - NACE International Annual Corrosion Conference CY - Phoenix, AZ, USA DA - 15.04.2018 KW - Geothermal KW - Coating KW - SiO2 KW - Polyaniline KW - Corrosion PY - 2018 AN - OPUS4-44918 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ackermann, H. A1 - Bäßler, Ralph T1 - Entwicklung einer Prüfmethode zur Bewertung der Materialbeständigkeit von Bauteilen in Mitteldestillatanwendungen N2 - Damit stehen neben den klassischen (Massenänderung der Werkstoffprüfkörpern und metallographischer Bewertung) neue Auswertemethoden für die Werkstoffbewertung zur Verfügung. T2 - DGMK Projekttreffen CY - Hamburg, Germany DA - 28.02.2018 KW - Korrosion KW - Brennstoff PY - 2018 AN - OPUS4-44932 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Raedel, Martina T1 - Mobile anodization for the conservation of damaged architectural aluminium elements N2 - Initial situation: Aluminum is an often-used building material in modern architecture, not only for construction but as well for facades and decorative elements. In the 1950th and 1960th, after World War II, many buildings in Germany were constructed with aluminum or contain elements of colored anodized aluminum. In the last years a larger number of these buildings are increasingly in the sight of conservation works including the aluminum parts such as window frames or facade coverings. Damaged Aluminum Surfaces: Common damages are a change of color or gloss changes through weathering processes, drill holes or marks due to later modifications, scratches in the anodized layer due to extensive wear e.g. at handrails or door handles. To repair damaged aluminum surfaces, there are usually two options: smaller damaged areas are repaired by using a touch-up pen. In case of larger damages, the complete re-anodization is necessary. This includes to de-anodize the surface with cleaning and grinding the whole aluminum object. Both possibilities are disadvantageous for the objects. The touch-up pen often does not match the color of the original surface together with an insufficient corrosion protection for outdoors. While the newly anodized surface differs in color and gloss from the originally applied color. Research Approach: The whole procedure contrasts with the principal approach in conservation which aims to intervene as less as possible, in case of the conservation of an object. To fulfill this approach in a more appropriate way the research project focuses on a mobile and partial application for colored, anodized aluminum parts. To anodize aluminum the application of an electrolyte onto the surface together with sufficient voltage and current is necessary. Generally diluted sulfuric acid is used as electrolyte. Different possibilities are examined to enable the mobile application of the electrolyte, e. g. the application by producing a gel matrix or like in electroplating by pen or brush wrapped with a fleece fabric. Experimental part: First experiments are conducted to examine the structure of the anodized layer in relation with proper cleaning, anodization time with applied voltage and current and the coloring process. The aim was to reduce the preparation procedure and the anodization time as much as possible to facilitate the mobile application. Examinations with Keyence microscope, Eddy current testing and REM are performed to characterize the layers. The results are shown in table 1. A clear connection between proper cleaning, anodization time, voltage and amperage and the achieved thickness of the anodized layer is significant. Cracks in the layer show that raising the voltage and amperage results in thicker layers but as well in a crumbled and less stable anodized surface. Gel preparation: In addition to the anodization process with a liquid e.g. sulfuric acid a gel application is tested to prevent the electrolyte from rinsing down during the mobile application. For this purpose, several gel-forming agents are tested together with their stability in acid systems. It was observed, that the consistency of the gels varies dependent of the time. Conductivity: The conductivity of sulfuric acid combined with different gel-systems was measured and compared in order to predict the possible growth of layers during anodic oxidation process. Further steps: Determination and optimization of application parameters like voltage, amperage and anodization-time to build up a preferably stable and sufficient thick anodized layer. Examination of gel preparation to guarantee a stable product, enforcing with textile tape for easy application. T2 - Architectural Aluminum in the 21st Century CY - Boston, MA, USA DA - 24.03.2018 KW - Aluminum KW - Anodization KW - Historic buildings KW - Mobile application PY - 2018 AN - OPUS4-45018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Le, Quynh Hoa T1 - Rezension: Röntgenfluoreszenzanalyse in der Laborpraxis N2 - Dieses Buch ist definitiv eine Empfehlung an alle, die mit RFA arbeiten müssen. Außerdem bietet es nützliche und praktische Informationen für Forscher, die an einem bestimmten Thema arbeiten, das im Antragsteil erwähnt wird. Dies wird ihnen während ihrer Forschung helfen, Proben vorzubereiten sowie Fehler in der RFA-Analyse zu erkennen und somit zu vermeiden. Die Stärken des Buches liegen im verständlichen Text und darin, dass alle notwendigen Schritte der Analysenverfahren Punkt für Punkt aufgeführt sind. Obwohl die Autoren eine unglaubliche Arbeit geleistet haben, um den Leser auf den neuesten Stand zu bringen, sind einige Teile ziemlich kurz gehalten. Die Auflistung von weiterführender Literatur, einschließlich wichtiger Normen und Gesetze, verringert dieses Manko etwas und verweist die interessierten Leser auf ergänzende Quellen. KW - Fluoreszenz KW - Oberflächenanalytik KW - Elementanalyse PY - 2018 DO - https://doi.org/10.1002maco.201870055 SN - 1521-4176 VL - 69 IS - 5 SP - 3 PB - WILEY-VCH Verlag GmbH & Co. KgaA CY - Weinheim AN - OPUS4-44930 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bäßler, Ralph T1 - Rezension: MATLAB und Mathematik kompetent einsetzen - Eine Einführung für Ingenieure und Naturwissenschaftler N2 - Zusammenfassend kann gesagt werden, dass dieses Buch seiner Intension, eine Brücke zwischen den in unteren Semestern erarbeiteten mathematischen Grundlagen und dem Einsatz der Mathematik im Ingenieuralltag sowie bei der wissenschaftlichen Modellierung und Analyse zu schlagen, gerecht wird. Es eignet sich zum Selbststudium sowohl für interessierte Studenten als auch erfahrene Praktiker. KW - MatLab KW - Programmierung KW - Gleichungssysteme PY - 2018 DO - https://doi.org/10.1002maco.201870055 SN - 1521-4176 VL - 69 IS - 5 SP - 2 PB - WILEY-VCH Verlag GmbH & Co. KgaA CY - Weinheim AN - OPUS4-44929 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bäßler, Ralph T1 - Rezension: Halliday Physik Lehr- und Arbeitsbuch N2 - Abschließend kann gesagt werden, dass dieses Buch umfassend in die einzelnen Bereiche der Physik einführt. Aufgrund seines modularen Aufbaus und der Kombination von Lehr- und Arbeitsbuch eignet es sich sehr gut zum Selbststudium. Für den Weg zum Seminar ist es aufgrund seines Gewichtes eher nichts. Es wird jedoch seinem Anspruch, ein unentbehrlicher Begleiter für das Physikgrundstudium zu sein, in jeder Hinsicht gerecht. KW - Physik KW - Energie KW - Arbeit KW - Thermodynamik KW - Gastheorie PY - 2018 VL - 69 IS - 4 SP - 4 PB - WILEY-VCH Verlag GmbH & Co. KgaA CY - Weinheim AN - OPUS4-44926 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lauer, Franziska T1 - Multivariate analysis of MALDI imaging mass spectrometry data of mixtures of single pollen grains N2 - Here, we present an advanced approach to identify pollen grains in mixtures based on: - a simplified sample preparation procedure - MALDI imaging mass spectrometry - chemometric tools Our goals are to: - explore the biomolecular variations in pollen - determine species-specific peak patterns - discriminate and identify single pollen grains in mixtures using MSI T2 - 66th Conference on Mass Spectrometry and Allied Topics CY - San Diego, CA, USA DA - 03.06.2018 KW - Pollen PY - 2018 AN - OPUS4-45196 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bäßler, Ralph T1 - Rezension: Wärmebehandlung von Eisenwerkstoffen II - Nitrieren und Nitrocarburieren N2 - Wie schon in den vorherigen Ausgaben bietet dieses Buch Studierenden der technischen Fach- und Hochschulen eine gute Unterstützung und ist insbesondere für die in der Industrie tätigen Techniker, Konstrukteure und Ingenieure zu empfehlen. Die aktualisierte Bibliographie von zum Thema einschlägigen Dissertationsschriften am Ende des Werkes bietet auch einen hohen Nutzen für den wissenschaftlichen Gebrauch. KW - Nitrocarburieren KW - Wärmebehandlung PY - 2018 DO - https://doi.org/10.1002maco.201870025 SN - 1521-4176 VL - 69 IS - 2 SP - 5 PB - WILEY-VCH Verlag GmbH & Co. KgaA CY - Weinheim AN - OPUS4-44924 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bäßler, Ralph T1 - Rezension: Lehrbuch der Metallkorrosion N2 - Zusammenfassend kann gesagt werden, dass dieses Lehrbuch einen prägnanten und verständlichen Einstieg in die Korrosion und den Korrosionsschutz liefert. Nicht nur der adressierten Zielgruppe, sondern auch anderen Interessenten bietet es einen kompakten Überblick über korrosionsrelevante Grundlagen und Aspekte. Jedoch vermisst der Rezensent eine Übersicht zu weiterführender Literatur, die für den interessierten Nutzer dieses Lehrbuches sicherlich für einen tieferen Einstieg in die Thematik nützlich wäre. KW - Korrosion KW - Korrosionsschutz KW - Elektrochemie PY - 2018 DO - https://doi.org/10.1002maco.201870045 SN - 1521-4176 VL - 69 IS - 4 SP - 5 PB - WILEY-VCH Verlag GmbH & Co. KgaA CY - Weinheim AN - OPUS4-44928 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witt, Julia T1 - Multilayer thin coatings for corrosion protection of AA2024-T3 aluminium alloy N2 - The performance of adhesively joined hybrid components relies strongly on the stability of the adhesive-material interface. With the increasing utilization of multi-material structures in the automotive and aerospace industry, it is of great scientific and technical interest to understand the processes leading to adhesive failure and to develop novel strategies to increase corrosion and delamination resistance of adhesive joints. The aim of this study is to develop thin epoxy based films and their carbon nanofiller loaded composites on aluminium alloy AA2024-T3 and to investigate their interfacial stability under corrosive and coupled corrosive-mechanical load. Spin coating was used for the layer-by-layer deposition of poly[(o-cresyl glycidyl ether)-co-formaldehyde] and poly-(ethylenimine) bi-layers. Carbon nanofillers are introduced either by mixing into the coating components or in between individual layers. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analysis was performed to investigate the porosity and water uptake of the model films, respectively. Atomic force microscopy (AFM) results indicated a very homogeneous and dense film with low surface roughness. The bi-layer thickness ranged between 30 to 40 nm. Electrochemical measurements show a higher corrosion resistance with the increase of the bi-layer number. The main novelty of this contribution is the in-situ AFM investigations under coupled corrosive-mechanical load. For this purpose, a tensile module capable of uniaxial stretching and compression with up to 5 kN force was integrated into the AFM stage. Stretching experiments were performed to investigate the mechanical properties and adhesion of the films, as well as structural changes of the film morphology during uniaxial deformation. The contribution will provide detailed information on the new AFM setup and summarize our results on the stability of model epoxy and nanocomposite films on AA2024-T3. T2 - EURADH 2018 CY - Lisbon, Portugal DA - 05.09.2018 KW - Electrochemical Empedance Spectroscopy (EIS) KW - Scanning Kelvin Probe Force Microscopy (SKPFM) KW - Corrosion KW - Delamination KW - Aluminium KW - Epoxide PY - 2018 AN - OPUS4-46513 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Özcan Sandikcioglu, Özlem T1 - Combined electrochemical techniques for the investigation of corrosion processes N2 - Short presentation of BAM, a summary of the methods available in FB 6.2 and recent results on MIC and high resolution corrosion studies T2 - Institute Seminar: Jerzy Haber Institute of Catalysis and Surface Chemistry CY - Cracow, Poland DA - 07.11.2018 KW - MIC KW - Corrosion KW - Atomic Force Microscopy (AFM) KW - Combined corrosive and mechanical load PY - 2018 AN - OPUS4-50313 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, Hans A1 - Weidner, Steffen T1 - High molar mass cyclic poly(L-lactide) via ring-expansion polymerizationwith cyclic dibutyltin bisphenoxides N2 - Two new catalysts (SnNa and SnBi) were prepared from dibutyltin oxide and 2,2′-dihydroxybiphenyl or2,2′dihydroxy(1,1′-binaphtyl). These catalysts enabled rapid polymerizations of L-lactide at 160 or 180 °C in bulk, whereby almost exclusively cyclic polylactides were formed. These polymerizations were free of racemization and yielded pol(L-lactide)s having weight average molecular weights (Mw's) up to 140 000 g mol−1. The Mw's varied little with the Lac/Cat ratio as expected for a ring expansion polymerization (REP). Polymerizations performed in bulk at 140, 120 and 102 °C yielded cyclic polylactides with lower molecular weights. At 102 °C a strong predominance of even-numbered cycles was found with SnNa as catalyst. SnNa can also catalyze alcohol-initiated ROPs yielding linear poly(L-lactide) free of cyclics. KW - MALDI-TOF MS KW - Polylactide KW - Ring-opening Polymerization KW - Cyclization KW - Catalysts PY - 2018 DO - https://doi.org/10.1016/j.eurpolymj.2018.05.036 SN - 0014-3057 SN - 1873-1945 VL - 105 SP - 158 EP - 166 PB - Elsevier Ltd. AN - OPUS4-45439 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Elsayed, H. A1 - Zocca, Andrea A1 - Schmidt, J. A1 - Günster, Jens A1 - Colombo, P. A1 - Bernardo, E. T1 - Bioactive glass-ceramic scaffolds by additive manufacturing and sinter-crystallization of fi ne glass powders N2 - Wollastonite (CaSiO 3 ) – diopside (CaMgSi 2 O 6 ) glass-ceramic scaffolds have been successfully fabricated using two different additive manufacturing techniques: powder-based 3D printing (3DP) and digital light processing (DLP), coupled with the sinter-crystallization of glass powders with two different compositions. The adopted manufacturing process depended on the balance between viscous flow sintering and crystallization of the glass particles, in turn in fluenced by the powder size and the sensitivity of CaO – MgO – SiO 2 glasses to surface nucleation. 3DP used coarser glass powders and was more appropriate for low temperature firing (800 – 900 °C), leading to samples with limited crystallization. On the contrary, DLP used finer glass powders, leading to highly crystallized glass-ceramic samples. Despite the differences in manufacturing technology and crystallization, all samples featured very good strength-to-density ratios, which bene fit theiruse for bone tissue engineering applications. The bioactivity of 3D-printed glass-ceramics after immersion in simulated body fluid and the similarities, in terms of ionic releases and hydroxyapatite formation with already validated bioactive glass-ceramics, were preliminarily assessed. KW - 3D-Printing KW - Bio Ceramic KW - Additive manufacturing PY - 2018 DO - https://doi.org/10.1557/jmr.2018.120 SN - 2044-5326 SN - 0884-2914 VL - 33 IS - 14 SP - 1960 EP - 1971 PB - Cambridge University Press AN - OPUS4-45718 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chi, Jinchun A1 - Zocca, Andrea A1 - Agea Blanco, Boris A1 - Melcher, J. A1 - Sparenberg, M. A1 - Günster, Jens T1 - 3D Printing of Self-Organizing Structural Elements for Advanced Functional Structures N2 - A shape evolution approach based on the thermally activated self-organization of 3D printed parts into minimal surface area structures is presented. With this strategy, the present communication opposes currently established additive manufacturing strategies aiming to stipulate each individual volumetric element (voxel) of a part. Instead, a 3D structure is roughly defined in a 3D printing process, with all its advantages, and an externally triggered self-organization allows the formation of structural elements with a definition greatly exceeding the volumetric resolution of the printing process. For enabling the self-organization of printed objects by viscous flow of material, functionally graded structures are printed as rigid frame and melting filler. This approach uniquely combines the freedom in design, provided by 3D printing, with the mathematical formulation of minimal surface structures and the knowledge of the physical potentials governing self-organization, to overcome the paradigm which strictly orrelates the geometrical definition of 3D printed parts to the volumetric resolution of the printing process. Moreover, a transient liquid phase allows local programming of functionalities, such as the alignment of functional particles, by means of electric or magnetic fields. KW - Additive Manufacturing KW - Self-Assembly KW - 3D-Printing KW - Polymeric Materials PY - 2018 DO - https://doi.org/10.1002/admt.201800003 SN - 2365-709X VL - 3 IS - 5 SP - 1800003-1 EP - 1800003-7 PB - Wiley-VCH CY - Weinheim AN - OPUS4-45714 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Panne, Ulrich T1 - Polymerwissenschaften@BAM - Sicherheit macht Märkte N2 - Die Bundesanstalt für Materialforschung und -prüfung (BAM) ist eine Ressortforschungseinrichtung, die zum Schutz von Mensch, Umwelt und Sachgüter, forscht, prüft und berät. Im Fokus aller Tätigkeiten in der Materialwissenschaft, der Werkstofftechnik und der Chemie steht dabei die technische Sicherheit von Produkten und Prozessen. Dazu werden Substanzen, Werkstoffe, Bauteile, Komponenten und Anlagen sowie natürliche und technische Systeme erforscht und auf sicheren Umgang oder Betrieb geprüft und bewertet. Schwerpunkt des Vortrages sind multimodale Polymeranalytik, nanoskalige Sensormaterialien und die Charakterisierung von technischen Eigenschaften von Polymeren sowie ihre Alterung und Umweltrelevanz. T2 - Institutsvortrag CY - Fraunhofer IAP, Potsdam, Germany DA - 18.05.2018 KW - Polymerwissenschaften PY - 2018 AN - OPUS4-45243 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Le, Quynh Hoa T1 - Acid condensation in pipeline transportation of impure CO2 N2 - CCS technology - Carbon Dioxide Capture and Storage, has been recognized as an excellent technology to reach the target of CO2 reduction. However, the safety issue and cost effectiveness currently hinder the future of CCS. Recent studies have shown that even at a very low concentration of impurities (less than 100 ppmV of SO2, NO2, O2 and H2O) the droplet formation and condensation of sulfuric and nitric acids in dense phase CO2 are possible and observable [1-3].To reveal the mechanism of droplet corrosion in dense CO2 at high pressure and low temperature, further studies on factors that affect wettability and resulting corrosion behaviors of transport pipeline steels are needed. In this work, carbon steel 1.8977 (L485MB), CrMo-alloyed steel 1.7225 (42CrMo4), martensitic steel 1.4313, and superaustenite steel 1.4562 (alloy 31) were investigated. The wettability was determined by contact angle measurement of sessile drop in CO2 atmosphere, at different pressure and temperature. The corrosion behavior of steels was investigated with standard exposure tests, followed by mass loss determination, surface characterization by scanning electron microscope (SEM) and chemical analysis by Energy Dispersive X-Ray Analysis (EDX). Exposure tests with and without the synthetic CO2 saturated water droplets were performed at both low temperature (278 K) and higher temperatures (288 K and 313 K) at high pressure where CO2 is supercritical or in dense phase. The investigated flue gases were SO2 (70-220 ppmV) and O2 (6700 ppmV) and water (50-200 ppmV). To reveal the effects of surface morphology, carbon steel coupons with different surface roughness were prepared to expose to CO2 stream containing oxidizing/reducing impurities to observe the condensation and the corrosion process that followed. T2 - 2. Jahrestagung der Fachgruppe Chemie und Energie CY - Müllheim (Ruhr), Germany DA - 30.09.2018 KW - CCUS KW - Supercritical/dense phase CO2 KW - Carbon steels KW - Martensitic steel KW - Superaustenite steel KW - Droplet corrosion PY - 2018 AN - OPUS4-46188 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stephan, Ina T1 - Pilze als Besiedler von Kulturgut: Wechselwirkungen mit Material erkennen und einschätzen N2 - Mikroskopische Pilze, die sich schnell auf verfügbaren Oberflächen ausbreiten können und die wir (wenn sie sich ansammeln), auch mit bloßem Auge erkennen können, werden Schimmelpilze genannt. Da diese Organismen verschiedene organische Kohlenstoffverbindungen als Nahrung benutzen, werden sie sich bei wachstumfördernden Feuchtigkeitsbedingungen in Bibliothekbeständen schnell ausbreiten können. Im Vortrag werden Haupteigenschaften aller Pilze, sowie auch aktuelle Methoden der Identifizierung dieser Organismen erörtert. Benutzung geeigneter Lebendkulturen als Referenzorganismen geben der Materialprüfung und -forschung eine Möglichkeit des reproduzierbaren Experimentierens mit verschiedenen Materialien und Simulation von Bedingungen im Gebrauch. Vorteile unserer Testverfahren sind: (i) Zeitraffung und Kontrollierbarkeit der Umweltparameter; (ii) Benutzung einer naturnahen Vergesellschaftung; iii) gezielte Variationen der Prüfbedingungen im Labor. Ziel dieser Untersuchungen ist einerseits biogene Schäden an neuen Materialien zu verfolgen und zu modellieren, und damit eine bessere Planungsgrundlage für die Materialentwicklung anzubieten. Andererseits werden mit den Referenzorganismen mikrobiologisch moderne und zeitraffende Techniken angeboten, die neue Behandlungsmethoden oder Pflegeverfahren für die Bestandserhaltung erwarten lassen. T2 - 8. Tag der Bestandserhaltung CY - Freie Universität Berlin, Berlin, Germany DA - 27.09.2018 KW - Kulturgut KW - Pilz KW - Schimmel KW - Bestandserhaltung PY - 2018 AN - OPUS4-46293 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kleinbub, Sherin T1 - The impact of methanogenic Archaea on material, environment and health N2 - Microbiologically influence corrosion (MIC) has become a big concern due the increased usage of different metals by our society. Microorganisms can use metal as an electron donor, causing unpredictable but serious damages. Nowadays it is known that besides sulfate reducing bacteria (SRB), other microorganisms including acetogens, iron oxidizers and methanogens can also induce MIC. Current studies related to methanogen-induced MIC (MI-MIC) mainly focused on environmental isolates from the oil and gas industry (e.g. Methanococcus maripaludis) with industrial materials e.g. iron. However, MI-MIC can occur in many other environments as well, including the oral cavity. Methanobrevibacter oralis is a methanogen isolated from the human oral cavity and was found more frequently in patients suffering from peri-implantitis/periodontitis. Titanium-implants removed from those patients have also showed clear signs of corrosion. The aim of our study is to establish and analyze corrosion potentials of dental metals (e.g. titanium) by oral methanogens. Periodontal pockets samples from patients suffering from periodontitis/peri-implantitis were taken for methanogenic and SRB enrichments. Stainless steel, pure titanium or Ti-6Al-4V alloy was used for corrosion studies. Corrosion rates and methane production were measured using weight-loss method and gas chromatography, respectively. Metal surfaces were visualized with scanning electron microscopy. Microbial communities in the dental pockets of healthy people and patients will be compared using 16S rRNA amplicon sequencing. Overall, this is the first study investigating the susceptibility of different dental implant materials to corrosion using human-related Archaea. The outcomes of this study can be further explored for a variety of clinical applications. T2 - ISME 17th International Symposium on Microbial Ecology CY - Leipzig, Germany DA - 12.08.2018 KW - Methanogens KW - Corrosion KW - Biofilm PY - 2018 AN - OPUS4-45932 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Blaeß, Carsten T1 - Sintering ability of fluoride-containing bioactive glass powder N2 - Sintered bioactive glass scaffolds of defined shape and porosity, e.g. made via additive manufacturing, must provide sufficient bioactivity and sinterability. As higher bioactivity is often linked to high corrosion and crystallization tendency, a certain compromise between sintering ability and bioactivity is therefore required. Groh et al. developed a fluoride-containing bioactive glass (F3), which allows fiber drawing and shows a bioactivity well comparable to that of Bioglass®45S5. To study whether and to what extent the sinterability of F3 glass powder is controlled by particle size, coarse and fine F3 glass powders (300-310µm and 0-32µm) were prepared by crushing, sieving and milling. Sintering, degassing and phase transformation during heating were studied with heating microscopy, vacuum hot extraction (VHE), DTA, XRD, and SEM. For the coarse glass powder, sintering proceeds slowly and is limited by surface crystallization of primary Na2CaSi2O6 crystals. Although the crystallization onset of Na2CaSi2O6 is shifted to lower temperature, full densification is attained for the fine powder. This finding indicate that certain porosity might be tuned via particle size variation. Above 900°C, intensive foaming is evident for the fine powder. VHE studies revealed that carbon species are the main foaming source. T2 - 92. Glastechnische Tagung CY - Bayreuth, Germany DA - 28.05.2018 KW - Sintering KW - Bioactive glass KW - Crystallization PY - 2018 AN - OPUS4-45568 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koerdt, Andrea T1 - Microbial corrosion of iron coupled to methanogenesis by strains from different environments N2 - Microbially influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) which act upon the metal by the reactiveness of hydrogen sulfide, and by withdrawal of the available electrons (Fe → Fe²⁺ + 2e⁻ ; E° = 0.47 V) in electrical contact through surface attachment. Also methanogenic archaea are supposed to cause MIC. Because they do not produce hydrogen sulfide, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood. Precipitation of siderite (4Fe + 5HCO₃⁻ + 5H⁺ → 4FeCO₃ + CH₄ + 3H₂O) can lead to an insulating layer on the metal surface and lower the corrosion rate. Still, the extent of FeCO₃ precipitation may be significantly influenced by environmental conditions such as pH and advective processes. To investigate the corrosive potential of methanogens, we studied strains isolated from marine sediments (Methanococcus maripaludis 14266, 2067, Methanobacterium-affiliated strain IM1), crude oil tanks (Methanococcus maripaludis Mic1c10, KA1) and the oral cavity (Methanobrevibacter oralis) in a closed (batch) culture, and in a sand-packed flow-through cell with pH control and simulation of a fluctuating environment. Results indicate that the rates of iron corrosion due to coupled methanogenesis (up to 0.3 mm/yr) are comparable to that caused by SRM. Surface analyses of the metal showed severe pitting. Such knowledge and deeper understanding also from an electrokinetic point of view may not only provide further models in microbial electrophysiology, but also contribute to mitigation strategies in MIC. T2 - ISME 17th International Symposium on Microbial Ecology CY - Leipzig, Germany DA - 12.08.2018 KW - Corrosion KW - Methanogens KW - Biofilm KW - Flow-System KW - Iron PY - 2018 AN - OPUS4-45735 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Orlov, Nikolai A1 - Milkin, P. A1 - Evdokimov, P A1 - Putlayev, V. A1 - Günster, Jens A1 - Nicolaides, Dagmar T1 - Bioceramics from Ca3(PO4)2 - CaKPO4 - CaNaPO4 system for bone replacement and grafting N2 - Biomaterials for bone replacement and grafting should possess sufficient strength, be bioresorbable and demonstrate osteoconductivity/osteoinductivity. Nowadays, hydroxyapatite (HA) and tricalcium phosphate (TCP) are the most widespread ceramics for bone grafting at the market, however, their resorption is reported, in some cases, to be not enough. This is why the search for more soluble ceramics compared to HA and TCP looks rather viable. A possible way to increase ceramics solubility leads to partial substitution of Ca2+-ions in Ca3(PO4)2 by alkali castions, like Na+ or/and K+. Improvement of solubility stems from decreasing lattice energy of a substituted phase, as well as increase in hydration energy of the ions releasing from the phase to ambient solution. From this viewpoint, bioceramics based on compositions from Ca3(PO4)2 - CaKPO4 - CaNaPO4 ternary system seems to be prospective for bone replacement and grafting in sense of resorption properties. At the same time, one should bear in mind that solubility level (resorbability) is governed not only by reduction of lattice energy, but also by microstructure features. Grain sizes and porosity contribute much to dissolution rate making study of sintering of aforementioned ceramics highly important. T2 - Biomaterials and Novel Technologies for Healthcare, 2nd International Biennial Conference BioMaH CY - Frascati (Rome), Italy DA - 08.10.2018 KW - Bio Ceramics KW - Bioresorbable PY - 2018 AN - OPUS4-46035 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bäßler, Ralph T1 - Korrosionsschutz in Theorie und Praxis N2 - Trotz teilweise nicht exakter Formulierungen und Terminologie bietet dieses Buch der angesprochenen Leserschaft einen umfassenden Einstieg in die Korrosionsthematik. Die am Ende jedes Kapitels aufgeführte Literatur liefert Beispiele zum vertiefenden Studium. Erwähnenswert ist auf jeden Fall die haptisch interessante Einbandgestaltung, die die Neugierde auf dieses Buch fördert. KW - Korrosion KW - Korrosionsschutz KW - Elektrochemie PY - 2018 DO - https://doi.org/10.1002maco.201870035 SN - 1521-4176 VL - 69 IS - 3 SP - 3 PB - WILEY-VCH Verlag GmbH & Co. KgaA CY - Weinheim AN - OPUS4-44925 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bäßler, Ralph T1 - Challenges for corrosion resistance of metallic materials in geothermal applications N2 - Corrosion aspects for use of metallic materials in geothermal applications are presented and discussed. T2 - Corrosion Workshop beim Geothermie Kongress 2018 CY - Essen, Germany DA - 27.11.2018 KW - Corrosion KW - Geothermal KW - Steel PY - 2018 AN - OPUS4-46744 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karl, D. A1 - Kamutzki, F. A1 - Zocca, Andrea A1 - Görke, O. A1 - Günster, Jens A1 - Gurlo, A. T1 - Towards the colonization of Mars by in-situ resource utilization: Slip cast ceramics from Martian soil simulant N2 - Here we demonstrate that by applying exclusively Martian resources a processing route involving suspensions of mineral particles called slurries or slips can be established for manufacturing ceramics on Mars. We developed water-based slurries without the use of additives that had a 51 wt. % solid load resembling commercial porcelain slurries in respect to the particle size distribution and rheological properties. These slurries were used to slip cast discs, rings and vases that were sintered at temperatures between 1000 and 1130 °C using different sintering schedules, the latter were set-up according the results of hot-stage microscopic characterization. The microstructure, porosity and the mechanical properties were characterized by SEM, X-ray Computer tomography and Weibull analysis. Our wet processing of minerals yields ceramics with complex shapes that show similar mechanical properties to porcelain and could serve as a technology for future Mars colonization. The best quality parts with completely vitrificated matrix supporting a few idiomorphic crystals are obtained at 1130 °C with 10 h dwell time with volume and linear shrinkage as much as ~62% and ~17% and a characteristic compressive strength of 51 MPa. KW - Ceramic KW - Mars PY - 2018 DO - https://doi.org/10.1371/journal.pone.0204025 SN - 1932-6203 VL - 13 IS - 10 SP - e0204025, 1 EP - 7 PB - Public Library of Science CY - San Francisco, Kalifornien, Vereinigte Staaten AN - OPUS4-46612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zocca, Andrea T1 - Powder-based Additive Manufacturing: beyond the comfort zone of powder deposition N2 - In powder-based Additive Manufacturing (AM) processes, an object is produced by successively depositing thin layers of a powder material and by inscribing the cross section of the object in each layer. The main methods to inscribe a layer are by binder jetting (also known as powder 3D printing) or by selective laser sintering/melting (SLS/SLM). Powder-based AM processes have found wide application for several metallic, polymeric and also ceramic materials, due to their advantages in combining flexibility, easy upscaling and (often) good material properties of their products. The deposition of homogeneous layers is key to the reproducibility of these processes and has a direct influence on the quality of the final parts. Accordingly, powder properties such as particle size distribution, shape, roughness and process related properties such as powder flowability and packing density need to be carefully evaluated. Due to these requirements, these processes have been so far precluded to find commercial use for certain applications. In the following, two outstanding cases will be presented. A first example is that powder-based AM processes are widely used for many metallic and polymeric materials, but they find no commercial application for most technical ceramics. This seemingly contradicting observation is explained by the fact that in powder based AM, a dry flowable powder needs to be used. The processing of technical ceramics in fact typically requires very fine and poorly flowable powder, which makes them not suitable for the standard processes. There have been several approaches to adapt the raw materials to the process (e.g. by granulation), but in order to maintain the superior properties of technical ceramics it seems necessary to follow the opposite approach and adapt the process to the raw materials instead. This was the motivation for developing the Layerwise Slurry Deposition (LSD), an innovative process for the deposition of powder layers with a high packing density. In the LSD process, a ceramic slurry is deposited to form thin powder layers, rather than using a dry powder. This allows achieving high packing density (55-60%) in the layers after drying. It is also important, that standard ceramic raw materials can be used. When coupled with a printing head or with a laser source, the LSD enables novel AM technologies which are similar to 3D printing or selective laser sintering, but taking advantage of having a highly dense powder bed. The LSD -3D printing, in particular, offers the potential of producing large (> 100 mm) and high quality ceramic parts, with microstructure and properties similar to traditional processing. Moreover, due to the compact powder bed, no support structures are required for fixation of the part in the printing process. Figure 1 shows the schematics of the working principle of the LSD-3D print and illustrates some examples of the resolution and features achievable. The second outstanding case here described is the application of powder-based AM in environments with reduced or zero gravity. The vision is to be able to produce repair parts, tools and other objects during a space mission, such as on the International Space Station (ISS), without the need of delivering such parts from Earth or carrying them during the mission. AM technologies are also envisioned to play an important role even for future missions to bring mankind to colonize other planets, be it on Mars or on the Moon. In this situation, reduced gravity is also experienced (the gravitational acceleration is 0.16 g on the Moon and 0.38 g on Mars). These environments cause the use of AM powder technologies to be very problematic: the powder layers need to be stabilized in order to avoid dispersion of the particles in the chamber. This is impossible for standard AM powder deposition systems, which rely on gravitation to spread the powder. Also in this case, an innovative approach has been implemented to face this technological challenge. The application of a gas flow through a powder has a very strong effect on its flowability, by generating a force on each particle, which is following the gas flow field. This principle can be applied in a simple setup such as the one shown in Figure 2. In this setup, the gas flow causes an average pressure on the powder bed in direction of the arrows, generating a stabilizing effect which acts in the same direction of the gravitational force. This effect can be used in addition to normal gravity on Earth to achieve a better stabilization of 3D printed parts in the powder bed. In this case, even a significant increase of packing density of the powder was measured, compared to the same experimental setup without gas flow. This is due to the fact that the force on each single particle follows the gas flow field, which is guiding the particles to settle between the pores of the powder bed, thus achieving an efficient packing. The same principle can be applied in absence of gravitation, where the gas flow acts to stabilize the powder layers. It has been shown that ceramic powder could be deposited in layers and laser sintered in µ-gravity conditions during a DLR (Deutsches Zentrum für Luft- und Raumfahrt) campaign of parabolic flights, as shown in Figure 2. A follow-up campaign is dedicated to the deposition of metallic (stainless steel) powder in inert atmosphere and to study the effects of laser melting in µ-gravity. In conclusion, the description of these two example cases shows how the development of novel technological processes can address some of the limitations of standard powder-based AM, in order to enable the use of new materials, such as technical ceramics, or to tackle the challenges of AM in space. T2 - WMRIF 2018 Early Career Scientist Summit CY - London, NPL, UK DA - 18.06.2018 KW - 3D-printing KW - Additive Manufacturing KW - Powder KW - SLM PY - 2018 AN - OPUS4-46338 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zocca, Andrea T1 - Layerwise Slurry Deposition for the Additive Manufacturing of Ceramics N2 - Powder bed -based technologies are amongst the most successful Additive Manufacturing (AM) techniques. "Selective laser sintering/melting" (SLS/SLM) and "binder jetting 3D printing" (3DP) especially are leading AM technologies for metals and polymers, thanks to their high productivity and scalability. In this context, the "layerwise slurry deposition" (LSD) has been developed as a layer deposition method which enables the use of SLS/SLM and 3DP technologies for advanced ceramic materials. LSD consists in the layer-by-layer deposition of a ceramic slurry by means of a doctor blade. Each layer is deposited and dried to achieve a highly packed powder layer, which can be used for SLM or for 3DP. This technique offers high flexibility in the ceramic feedstock used, especially concerning material and particle size, and is capable of producing parts with physical and mechanical properties comparable to traditionally shaped parts. In this presentation, the LSD technique will be introduced and several examples of application to porcelain, SiC and alumina products will be reported. T2 - CIMTEC - International Ceramics Congress CY - Perugia, Italy DA - 04.06.2018 KW - Ceramic KW - Additive Manufacturing PY - 2018 AN - OPUS4-46337 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Saadeh, Qais T1 - In-Situ SAXS Techniques N2 - Our project's aim is to enhance the capabilities of additive manufacturing techniques, where enabling a Two-Photon-Polymerization (TPP) 3D printer of producing arrays of precisely aligned nanoparticles is of an enormous value. As heterogeneous functional nanostructures with arrays of oriented nanoparticles are very promising in many fields; electrochemistry, energy storage, nanoelectronics among other vital fields. The feasibility and the convenience of orienting nanoparticles using magnetic, electric fields and ultrasonic vibrations will be systematically investigated, using Small Angle X-ray Scattering (SAXS), since SAXS can provide detailed information about the orientation characteristics of nano-Ensembles. Corresponding to our prerequisites, a set ad hoc functional sample holders, sample stages and other In-Situ SAXS solutions were developed, and incorporated to be compatible with a state-of-the-arts SAXS machine, called Multi-scale Analyzer for Ultrafine Structures (MAUS). The MAUS has been customized and engineered to serve as a miniaturized synchrotron, and that is exactly what we need. Experiments attempting to orient superparamagnetic nanoparticles will be discussed, where the outcomes will not only help in understanding the mechanics of field-particle interactions, it will also help in further developing the adequate needed set of corrections to the SAXS data, that is especially regards oriented samples. T2 - XVII International Small Angle Scattering Conference – SAS 2018 CY - Traverse City, Michigan, USA DA - 07.10.2018 KW - In-Situ Techniques KW - SAXS KW - Magnetic nano-particles PY - 2018 AN - OPUS4-46443 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wurzler, Nina T1 - Effect of conditioning layers on the attachment and biofilm formation of electroactive bacteria on stainless steel N2 - The characteristics of different molecules chosen as representatives for specific functionalities in conditioning layers play an important role on attachment behavior and later biofilm formation of bacteria. The chemical composition is a major component influencing the attachment but there is a conglomerate of influences. T2 - Eurocorr2018 CY - Krakow, Poland DA - 09.09.2018 KW - Conditioning layer KW - Stainless steel KW - Bacterial attachment PY - 2018 AN - OPUS4-46487 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -