TY - CONF A1 - Kauss, N. A1 - Rosemann, Paul A1 - Halle, T. T1 - Age-hardening behaviour, microstructure and corrosion resistance of the copper alloyed stainless steel 1.4542 N2 - The copper alloyed stainless steel 1.4542 (X5CrNiCuNb16-4) is used in different areas due to its good mechanical properties and corrosion resistance. Strength and corrosion re-sistance can be adjusted by the heat treatment, which is of importance for the application of this alloy. The mechanical properties (strength and hardness) are attributed to the dispersive precipitation of the copper rich ε–Phase. The additional precipitation of chromium carbides can reduce the corrosion resistance. Different ageing states were produced to investigate the precipitation behaviour with various methods. Furthermore, the influence of cold-rolling on the precipitation behaviour was studied in comparison to a solution annealed state without deformation. The microstructure was studied by SEM and the variations of hardness and magnetic proportion were characterised. The electrochemical potentiodynamic reactivation (EPR) was used to determine the corrosion resistance and detect chromium depletion in all heat-treated states. The results show that a work hardening accelerates the precipitation rate, while ageing at 600 °C reduces the corrosion re-sistance due to chromium depletion. T2 - EUROCORR 2018 CY - Krakow, Poland DA - 09.09.2018 KW - Corrosion KW - Stainless steel KW - Corrosion resistance KW - EPR KW - Corrosion testing KW - Heat treatment KW - ThermoCalc KW - REM KW - Martensitic stainless steels PY - 2018 AN - OPUS4-45955 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Yildirim, Arda A1 - Sentker, Kathrin A1 - Huber, Patrick A1 - Schönhals, Andreas T1 - Collective Orientational Order and Phase Behavior of a Discotic Liquid Crystal under Confinement N2 - Discotic liquid crystals (DLCs) are a promising class of soft matter for electronic applications. This is due to their ability to self-organize into columns in a hexagonal columnar mesophase, driven by the overlapping of the π orbitals of their aromatic cores. This leads to a high charge-carrier mobility along the column axis. Embedding liquid crystals into nanopores of anodic aluminum oxide (AAO) results in a 2D nanoconfinement of these materials. This confinement affects their properties, compared to the bulk, such as phase transition temperatures and enthalpies, molecular mobility, and crystallization. In this study, 2,3,6,7,10,11 hexakis[hexyloxy] triphenylene (HAT6) was confined into parallel aligned cylindrical nanopores of AAO membranes by melt infiltration. The membrane as confining hosts used have varying pore diameters, from 10 nm to 160 nm, covering a broad pore size range, thus, a better understanding of the confinement effect on phase behavior and molecular configuration in the pores. Furthermore, it is aimed to obtain axial ordering or to increase degree of axial ordering by chemically modifying the surfaces of the pores. Therefore, the pore surfaces the membranes were chemically modified, resulting in a more hydrophobic pore surface than the unmodified ones. The phase behavior was explored by a power-compensated DSC allowing the detecting of small changes in the phase behavior. In the literature, dielectric spectroscopy was demonstrated as a method to monitor molecular order inside the pores. Here, we also investigate the collective orientational order, corresponding to dominating molecular ordering, by dielectric spectroscopy. T2 - 10th Conference on Broadband Dielectric Spectroscopy and its Applications CY - Brussles, Belgium DA - 26.08.2018 KW - Confined Columnar Liquid Crystals PY - 2018 AN - OPUS4-45916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Madkour, Sherif A1 - Schönhals, Andreas T1 - Molecular dynamics of an asymmetric PVME/PS Blend investigated by broadband dielectric and specific heat spectroscopy N2 - Over the past decades research on the molecular dynamics of miscible polymer blends are of topical interest in the literature, in an attempt to understand the segmental mobilty of individual components, as it is affected by blending. In general, miscible polymer blends exhibit a complex behavior of the molecular mobility. For an A/B blend the relaxation times of component A and component B are affected by the spatial local compositional heterogeneity, present in binary systems on a microscopic level, regardless of the macroscopic homogeneity. Here, a combination of broadband dielectric and specific heat spectroscopy was employed to study the dynamically asymmetric PVME/PS blend with seven different compositions, focusing on samples with high PS contents. Considering that PS is dielectrically invisible, BDS is a powerful technique to study the response of PVME, as it is affected by PS segments. In this work the well-known binary relaxation times distribution of PVME in a blend, originating from the spatial local heterogeneity, was studied over ten decades in frequency, for the first time in literature. Secondly, one of the detected processes, α’-relaxation, shows a crossover from high-temperature behavior (system in equilibrium) towards a low temperature regime, where PS undergoes the thermal glass transition, resulting in confined segmental dynamics of PVME within a frozen network of PS. Here, we introduce a precise mathematical tool to distinguish between the temperature dependency regimes of the process, and examine the composition dependence of the crossover temperature, detected by dielectric spectroscopy. Moreover, the dielectric data was compared in detail with results obtained by specific heat spectroscopy. This comparison provides new insights in the dynamics and dynamic heterogeneity of the PVME/PS blend system. T2 - 10th Conference on Broadband Dielectric Spectroscopy and its Applications CY - Brussels, Belgium DA - 26.08.2018 KW - Polymer blends KW - Dielectric spectroscopy KW - Specific heat spectroscopy PY - 2018 AN - OPUS4-45917 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Yildirim, Arda A1 - Sentker, Kathrin A1 - Bühlmeyer, Andrea A1 - Laschat, Sabine A1 - Huber, Patrick A1 - Schönhals, Andreas T1 - Molecular dynamics of dipole functionalized triphenylene-based discotics N2 - Since discovery of discotic liquid crystals (DLCs), consisting of a disklike rigid aromatic core and flexible alkyl chains attached to the core, dating back to Chandrasekhar’s work in 1977, they have been extensively investigated to reveal their fundamental properties and potential for applications. The researches on DLCs in last decades showed that DLCs can be considered as promising materials for organic electronic applications since they exhibit one dimensional high charge mobility along the column axis in a columnar mesophase. The mobilies of the rigid aromatic core and the flexible alkyl chains can influence their application properites, e.g. the charge carrier mobility, therefore, it needs to be explored in detailed. In this study, a series of dipole functionalized triphenylene-based discotics, forming a columnar mesophase, were investigated to reveal the influence of the functionalization on phase behavior, molecular dynamics and as well as conductivity. The molecular mobility of the discotics was probed by broadband dielectric spectroscopy (BDS). In addition to conductivity and localized dynamics, glassy dynamics were also observed. The phase behavior of the material was explored by a power-compansated differential scanning calorimetry (DSC). Beside the phase transition temperatures and enthalpies, thermal glass transitions were found for all the materials. Moreover, the glassy dynamics were further investigated by Flash DSC, which is a chip-based calorimetry technique allows fast heating and cooling rates as high as 10000K/s. T2 - 10th Conference on Broadband Dielectric Spectroscopy and its Applications CY - Brussles, Belgium DA - 26.08.2018 KW - Columnar liquid crystals PY - 2018 AN - OPUS4-45918 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Madkour, Sherif A1 - Schönhals, Andreas T1 - Dynamics of nanoscopically confined PVME in thin films of an asymmetric miscible PVME/PS blend N2 - In recent years, substantial efforts have been devoted to investigating nanoscopic confinement of polymers, and its effect on glassy dynamics. Broadband Dielectric Spectroscopy (BDS) was used to study the dynamics of ultra-thin films of PVME/PS 50/50 wt% blend, employing a novel nano-structured capacitor sample arrangement. The investigated system shows a complex dynamic behavior. First, an α-relaxation, related to a bulk-like layer was found. Second, an α’-relaxation was observed, characteristic for dynamically asymmetric blends, where the out of equilibrium dynamics is attributed to weakly-cooperative PVME segments relaxing within a frozen environment of PS segments. Third, for thinnest films, an Arrhenius-like process was dominant in the dielectric spectra, indicating localized fluctuations of the segments. Relaxation rates of this process resembled that of the degenerated α-relaxation of the adsorbed layer, found for pure PVME [1], thus it was assigned accordingly. For thinnest films, this process undergoes a further confinement, due to the topological constraints, introduced by PS. Such multiple confinement effect has not been reported for ultra-thin films of polymer blends, before this study [2]. [1] Madkour, S. et al. ACS Appl. Mater. Interfaces 2017, 9, 7535. [2] Madkour, S. et al. ACS Appl. Mater. Interfaces 2017, 9, 37289. T2 - 10th Conference on Broadband Dielectric Spectroscopy and its Applications CY - Brussels, Belgium DA - 26.08.2018 KW - Polymer blends KW - Thin polymer films KW - Dielectric spectroscopy KW - Specific heat spectroscopy PY - 2018 AN - OPUS4-45919 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Léonard, Fabien A1 - Bruno, Giovanni T1 - Metrology for Additively Manufactured Medical Implants: The MetAMMI project N2 - Additive manufacturing (AM) offers an effective solution to the medical sector. It enables the production, on demand, of customised implants which match the patient’s anatomy, with grafts that promote bone growth, as well as surgical guides that help the surgeons. The objective of this project is to provide a comprehensive basis to enable the safe use of medical AM products with traceable and reliable dimensionalmeasurements. This will guarantee the reliability of medical AM products to notified bodies and facilitate acceptance of AM in the medical sector for a better quality of life. T2 - BPWT/BAM Workshop " Innovative Materialien und Qualitätskontrolle für additive Fertigung" CY - Berlin, Germany DA - 12.09.2018 KW - Additive manufacturing KW - X-ray computed tomography PY - 2018 AN - OPUS4-45926 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weltschev, Margit A1 - Hoffmann, Gabi A1 - Rehfeldt, Rainer A1 - Kohl, Anka T1 - Investigations on the degree of damage of polyethylene grades as materials of heating oil storage tanks after a service life of more than 30 years N2 - Tanks for heating oil made of polyethylene grades have been on the market since the early 1970s in Germany. Tank manufacturers recommend the replacement of the tanks after a period of 30 years due to guarantee safety. Polyethylene grades are subject to ageing by alteration of the properties during their life cycle. The degree of ageing and the nature of the degradation process mainly depend on the chemical degradation of the polyethylene, the wall thickness of the tank and the environmental conditions. There are no results available on the long-term behavior of the polyethylene grades, especially after a service life of more than 30 years. The aim of this investigation was the determination of the factual degree of damage in comparison to the uncontaminated polyethylene grades. Material data of the used polyethylene grades are available because the BAM was the competent authority for the tests and expert reports for the approval of these tanks until the middle of the 1990s. The determination of the Melt Flow Rate (MFR) and the Fourier Transmission IR Spectroscopy (FTIR) of tank sections from the bottom, the shell and the roof of 10 segregated heating oil storage tanks produced of polyethylene grades A and B were used as tests methods. The MFR measurements of the tank sections showed differences in the values depending on the weight which was used (5 kg or 21.6 kg). A reduction of the MFR values was measured for most of the sections of tanks made of polyethylene grade B after a service life of the tanks of more than 30 years. This grade is mainly subject to the internal ageing by cross-linkages, increased degree of branched molecules and loss of the plasticizer, and to a lesser extent by oxidative degradation. The FTIR analysis, especially of tank sections of the bottom and the shell showed that the intensity of the CH2 asymmetric and symmetric stretching vibrations in the range: 2800 - 2900 cm-1 and the CH2 bending deformation vibration at 1400 cm-1 increased due chain scissions. The intensity of the carbonyl stretching vibration C=O at 1740 cm-1 is low. The carbonyl index characterizes the degree of oxidation. T2 - EUROCORR 2018 CY - Krakow, Poland DA - 09.09.2018 KW - Heating oil storage tanks KW - Polyethylene KW - Degree of damage KW - Melt Flow Rate (MFR) KW - FTIR PY - 2018 AN - OPUS4-45939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Torge, Manfred A1 - Feldmann, Ines A1 - Seneschal-Merz, Karine A1 - Bücker, Michael A1 - Oleszczuk, O. 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 - CONF A1 - Beckmann, Jörg A1 - Schade, U. A1 - Jaunich, Matthias A1 - von der Ehe, Kerstin A1 - Wolff, Dietmar T1 - THz- and MIR FTIR Spectroscopy on Polyethylene, N2 - THz and mid IR spectroscopy of high-molecular PE (HMW) and ultra high-molecular PE (UHMW) reveals modifications of the molecular structure. Characteristic absorption bands are changed if the two materials are exposed by -Co60 radiation up to 600 kGy and subsequently stored at an annealing temperature of 398 K until for 729 days. UHMW-PE and HMW-PE behave differently during the ageing process because of their molecular weight and inherent structure distinctions. The spectroscopic data offer characteristic absorption bands, which have been used to describe the complete ageing process in more detail. For instance, the integral absorption in the B1u THz-region can be used to describe quantitatively the reduction of crystallinity. The formation of trans vinylene unsaturation and the decay of vinyl during ageing can be observed in detail in the mid IR range. T2 - IRMMW-THz 2018 (43rd) Conference CY - Nagoya, Japan DA - 09.09.2018 KW - Gamma-Co60 radiation KW - THz and mid IR spectroscopy PY - 2018 AN - OPUS4-46442 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witt, Julia A1 - Almalla, Ahed A1 - Özcan Sandikcioglu, Özlem 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 - Pietsch, Franziska A1 - Schreiber, Frank T1 - Selection of resistance in bacterial biofilms grown on antimicrobial surfaces in a multidrug environment N2 - Background Bacterial biofilms are regarded as the most common cause of chronic infections and are often associated with medical devices, such as implants and catheters. Bacteria growing in biofilms produce a protective, extracellular matrix, which enables them to tolerate much higher antimicrobial concentrations than free-living bacteria and survive long enough to acquire antimicrobial resistance. Preventive and therapeutic strategies against biofilm infections in clinical settings commonly involve the application of multiple antimicrobials: biocidal coatings on the biomaterials and systemically administered antibiotics. This frequent practice harbors the risk of the development of cross-resistance via shared resistance mechanisms between antimicrobials used in material coatings and administered antibiotics. Aim Our goal is to determine how bacteria adapt to antimicrobials during biofilm formation on surfaces coated with antimicrobials and how population dynamics within biofilms affect the transmission of resistance mutations. Specifically, we want to identify antimicrobial-antibiotic-combinations that select for and against antibiotic resistance in biofilms by following the population dynamics of resistant and susceptible strains in competition assays on a single cell level. Methodology To study the effect of antimicrobial-antibiotic exposure on resistance development and population dynamics on bacterial biofilms in a multidrug environment, we will grow Pseudomonas aeruginosa on glass surfaces with and without antimicrobial coatings and expose them to antibiotics. First, we will screen in vitro for combinations of antibiotics and antimicrobials that select for and against antibiotic resistance. Second, effective combinations will be chosen for in-depth investigations during bacterial adhesion and of mature biofilms of resistant and susceptible genotypes. Third, based on the outcome of the screen and the obtained mechanistic understanding we will choose a clinical example in which we study the relevance of our findings in biofilms grown in vivo. Relevance Studying the biointerfacial interactions between bacterial biofilms and medical devices in terms of population dynamics as well as on single cell level during multidrug selection will help us understand how drug resistance develops and spreads in persistent biofilm infections. Based on our findings we aim to provide clinical recommendations for improved administration of antibiotics/antimicrobials in combination with medical device materials in order to mitigate against biofilm associated antimicrobial resistance. T2 - Biofilms 8 Conference CY - Aarhus, Denmark DA - 27.05.2018 KW - Resistance KW - Antimicrobials PY - 2018 AN - OPUS4-46524 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - An, Biwen Annie A1 - Kleinbub, Sherin A1 - Schreiber, Frank A1 - Koerdt, Andrea T1 - Investigating the effects of biocides and corrosion inhibitors on corrosive methanogens N2 - Microbiologically influenced corrosion (MIC) is the deterioration of metals due to the metabolic activities of microorganisms. Microorganisms can take electrons directly from the metal surface (EMIC) thereby causing corrosion. Well known culprits of EMIC are: sulfate-reducing bacteria (SRB), acetogens and methanogens. Our aims - Develop a novel flow system to study MIC by methanogens to mimic industrial Environments - Investigate the inhibitory concentrations of biocides targeting SRB on corrosive methanogenic strains - Investigate the inhibitory effects of corrosion inhibitors on methanogens - Compare the inhibitory concentrations to SRB T2 - BAM meeting CY - BAM, Berlin, Germany DA - 06.06.2018 KW - MIC projekt KW - Mikrobiell beeinflusste Korrosion KW - Microbiologically influenced corrosion KW - Korrosion KW - Corrosion KW - Material degradation KW - Biocide PY - 2018 AN - OPUS4-46010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rosemann, Paul A1 - Baumann, O. A1 - Müller, C. T1 - Influence of the post-weld surface treatment on the corrosion resistance of the duplex stainless steel 1.4062 N2 - The duplex stainless steel 1.4062 (X2CrNiN22-2) is used as alternative material to austenitic stainless steels in the construction industry. The corrosion resistance of welded seams is influenced by the base material, the weld filler material, the welding process and also by the final surface treatment. The scale layer next to the weld seam can be removed by grinding, pickling, electro-polishing or blasting depending on the requested corrosion resistance. Blasted surfaces are often used in the industrial practice due to the faster and cheaper manufacturing process compared to pickled or electro-polished surfaces. Furthermore blasting with corundum-grain is more effective than blasting with glass-beads which also lower the process costs. In recent years, stainless steel surfaces showed an unusually high susceptibility to pitting corrosion after grinding with corundum. For this reason, it is now also questioned critically whether the corrosion resistance is influenced by the applied blasting agent. This question was specifically investigated by comparing grinded, pickled, corundum-grain- and glass-bead-blasted welding seams. Results of the SEM analyses of the blasting agents and the blasted surfaces will be presented and correlated with the results of different corrosion tests (KorroPad-testing and pitting potentials). T2 - Materials Science and Engineering 2018 (MSE) CY - Darmstadt, Germany DA - 26.09.2018 KW - Duplexstahl KW - Korrosion KW - Nichtrostender Stahl KW - Schweißen KW - Oberflächenbearbeitung KW - Strahlen KW - KorroPad PY - 2018 AN - OPUS4-46090 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Evans, Alexander T1 - AGIL Project - Microstructure development in additively manufactured metallic components: from powder to mechanical failure N2 - Overview of the concept of the AGIL Project, work packages and Prior published work from BAM on the subject T2 - Challenges in Additive Manufacturing: Innovative Materials and Quality Control CY - BAM, Berlin-Adlershof, Germany DA - 12.09.2018 KW - AGIL KW - Additive manufacturing PY - 2018 AN - OPUS4-46100 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 - CONF A1 - Koerdt, Andrea A1 - An, Biwen Annie A1 - Özcan Sandikcioglu, Özlem A1 - Widdel, F. 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 - CONF A1 - Koerdt, Andrea A1 - An, Biwen Annie A1 - Özcan Sandikcioglu, Özlem A1 - Widdel, F. 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 - ISME CY - Leipzig, Germany DA - 12.08.2018 KW - Methanogens KW - MIC KW - Corrosion KW - Environmental Simulation PY - 2018 AN - OPUS4-46397 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pietsch, Franziska A1 - Schreiber, Frank T1 - Selection of Resistance in Bacterial Biofilms Grown on Antimicrobial Surfaces in a Multidrug Environment N2 - Background Bacterial biofilms are regarded as the most common cause of chronic infections and are often associated with medical devices, such as implants and catheters. Bacteria growing in biofilms produce a protective, extracellular matrix, which enables them to tolerate much higher antimicrobial concentrations than free-living bacteria and survive long enough to acquire antimicrobial resistance. Preventive and therapeutic strategies against biofilm infections in clinical settings commonly involve the application of multiple antimicrobials: biocidal coatings on the biomaterials and systemically administered antibiotics. This frequent practice harbors the risk of the development of cross-resistance via shared resistance mechanisms between antimicrobials used in material coatings and administered antibiotics. Aim Our goal is to determine how bacteria adapt to antimicrobials during biofilm formation on surfaces coated with antimicrobials, how antimicrobial resistance mutations are acquired and evolve within mature biofilms, and how population dynamics within biofilms affect the transmission of resistance mutations. Specifically, we want to identify antimicrobial-antibiotic-combinations that select for and against antibiotic resistance in biofilms by following the population dynamics of resistant and susceptible strains in competition assays. Methodology We will grow biofilms of Pseudomonas aeruginosa on glass surfaces with and without antimicrobial coatings and expose them to antibiotics. Then we will track their physiological properties, evolutionary adaptations, and population dynamics. First, we will screen in vitro for combinations of antibiotics and antimicrobials that select for and against antibiotic resistance. Second, effective combinations will be chosen for in-depth investigations during bacterial adhesion and of mature biofilms of resistant and susceptible genotypes. Third, based on the outcome of the screen and the obtained mechanistic understanding we will choose a clinical example in which we study the relevance of our findings in biofilms grown in vivo. Relevance Studying the biointerfacial interactions between bacterial biofilms and medical devices in terms of population dynamics as well as on single cell level during multidrug selection will help us understand how drug resistance develops and spreads in persistent biofilm infections. Based on our findings we aim to provide clinical recommendations for improved administration of antibiotics/antimicrobials in combination with medical device materials in order to mitigate against biofilm associated antimicrobial resistance. T2 - Challenges and New Concepts in Antibiotic Research CY - Paris, France DA - 19.03.2018 KW - Resistance KW - Antimicrobials PY - 2018 AN - OPUS4-46398 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Bernd R. A1 - Cabeza, Sandra A1 - Pereyra, R. A1 - Fernández, R. A1 - González-Doncel, G. A1 - Kupsch, Andreas A1 - Bruno, Giovanni T1 - Evidence of damage evolution during creep of Al–Mg alloy using synchrotron X-ray refraction N2 - In order to provide further evidence of damage mechanisms predicted by the solid-state transformation creep (SSTC) model, direct observation of damage accumulation during creep of Al–3.85Mg was made using synchrotron X-ray refraction (SXRR). X-ray refraction techniques capture the specific surface (i.e. surface per unit volume) with a field of view comparable to the specimen size but with microscopic sensitivity. A significant rise of the internal specific surface with increasing creep time was observed, providing evidence for the creation of a fine grain substructure, as predicted by the SSTC model. T2 - Tenth Joint BER II and BESSY II User Meeting CY - Berlin, Germany DA - 05.12.2018 KW - Aluminium alloys KW - Creep KW - Damage KW - Synchrotron X-ray refraction KW - Electron microscopy KW - Subgrain structure PY - 2018 AN - OPUS4-46861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Breitfeld, Steffen A1 - Scholz, Gudrun A1 - Emmerling, Franziska A1 - Kemnitz, Erhard T1 - High energy ball milling of a new representative of coordination polymers without organofluorine linkers N2 - Metal organic frameworks and coordination polymers play an important role in different fields of applications. Moreover, particularly fluorinated metal-organic frameworks (FMOFs) are in the focus of interest during the last years. In most cases, fluorine is implemented using perfluorinated organic linkers at the synthesis, usually performed by solvothermal synthesis. However, only few examples are known so far where fluorine is coordinated directly to the metal cation. Recently, we reported about mechanochemical syntheses and characterization of fluorine-containing coordination polymers of alkaline earth metals by milling M(OH) (M: Ca, Sr, Ba) with fluorinated benzene dicarboxylic acids 2 and we reported about mechanochemical syntheses of alkaline earth metal fluorides with ammonium fluoride. Now we are reporting about a combination of both synthesis routes. That is the first mechanochemical synthesis of coordination polymers where fluorine is coordinated directly to the metal cation. T2 - Konferenz CY - Berlin, Germany DA - 30.11.2017 KW - Metal organic frameworks KW - Coordination polymer KW - Mechanochemical syntheses KW - Direct fluorine-metal bond KW - Alkaline earth metal PY - 2017 AN - OPUS4-46898 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kabelitz, Anke A1 - Dinh, H. A. A1 - Emmerling, Franziska T1 - A02: In situ WAXS studies on the crystallization of Al 13 keggin clusters in water N2 - Polynuclear aluminium species (Al13 keggin cluster) find application in different areas like water purification [1], contaminant transport [2], and as pilling clays with high specific surface areas[3], due to their strong binding ability to aggregates and high positive charge. In the present contribution, we report on the in situ investigation of the Al13 sulfate synthesis by synchrotron wide-angle X-ray scattering (WAXS). Al13 cluster were crystallized by precipitating hydrolyzed aluminum solutions by the addition of sodium sulfate. The measurements were performed using a custom-made acoustic levitator as sample holder. The study provides information about the intermediates during the crystallization process. From the data, a mechanism was derived indicating the influence of the crystallization process. T2 - Final Meeting of the CRC 1109 & Edith Flanigen Award Ceremony 2018 CY - Berlin, Germany DA - 10.10.2018 KW - Crystallization KW - WAXS KW - Keggin Cluster PY - 2018 AN - OPUS4-47005 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kabelitz, Anke A1 - Emmerling, Franziska A1 - de Oliveira Guilherme Buzanich, Ana A1 - Kraehnert, R. A1 - Kraffert, K. A1 - Schmack, R. T1 - In-situ characterisation of nucleation, growth, crystallisation and dissolution of nanoscaled iron oxides N2 - We present the synthesis of four mesoporous templated iron oxides: Ferrihydrite, Hematite, Maghemite, Magnetite/Maghemite and the influence of water on the crystallization mechanism and the kinetics. The absence of water stabilize the ferrihydrite structure. By monitoring the dissolution in situ by using a QCMB and ex situ microscopy we got details in the dissolution mechanism of ferrihydrite. T2 - Final Meeting of the CRC 1109 & Edith Flanigen Award Ceremony 2018 CY - Berlin, Germany DA - 10.10.2018 KW - Mesoporous KW - Iron oxide KW - Mechanism PY - 2018 AN - OPUS4-47010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rütters, H. A1 - May, Franz A1 - Bettge, Dirk A1 - Fischer, S. A1 - Ganzer, L. A1 - Jäger, P. A1 - Kather, A. A1 - Lempp, C. A1 - Lubenau, U. T1 - Combining CO2 Streams from Different Emitters – A Challenge For Transport And Storage Infrastructure N2 - The European Directive 2009/31/EC on the geological storage of CO2 envisages an open access of CO2 streams from different emitters to a nation- or even EUwide CO2 pipeline network if CO2 stream compositions meet “reasonable minimum composition thresholds”. As of today it is not known how such “composition thresholds” may be defined and which impurity levels may be viable in practical application. To set up recommendations for criteria and respective threshold values for CO2 stream compositions, the project “CLUSTER” will investigate how a dynamic interplay – both in terms of mass fluxes and compositions – of CO2 streams from regionally clustered CO2 sources sharing a transport and storage infrastructure will impact corrosion, e.g., of pipelines and plant components, and geochemical alteration of cap rocks and reservoir rocks. In addition, the behaviour of such a highly dynamic CCS system will be considered for an overall optimization of system design including CO2 stream mixing schemes and facilities or interim CO2 storage. T2 - TCCS-8 – The 8th Trondheim Conference on CO2 Capture, Transport and Storage CY - Trondheim, Norway DA - 16.06.2015 KW - Carbon capture KW - Carbon dioxide KW - Corrosion KW - CCS PY - 2015 AN - OPUS4-47018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Blaeß, Carsten A1 - Müller, Ralf A1 - Thompson, Cyrus T1 - Crack healing in glasses N2 - Fundamental understanding of crack healing in glassy crystalline materials is very important for many applications, especially for solid oxide fuel cells (SOFC) sealants since cracks caused by mechanical stress or thermal cycling still remain a substantial bottleneck in developing durable SOFC. Previous studies on soda lime silicate glass published by Singh showed that crack healing is driven by viscous flow. There he postulated that the healing progress is proportional to time, t, and the inverse viscosity. This finding would allow to present for a given glass data of crack healing measured at different temperatures in a master curve, if the healing progress is plotted versus t/η. Such master curves would be a helpful tool in understanding crack healing kinetics. To verify the applicability of such master curves, crack healing in non-crystallizing soda-lime-silicate (NCS) and sodium-borosilicate glasses (NBS) was studied. Cracks were generated by Vickers indention and healed isothermally at different temperatures. Crack healing progress was monitored by optical and electron microscopy. The results show that the above mentioned proportionalities applies to the two glasses. In both cases the afore developed master curve could be obtained. T2 - 91. Jahrestagung HVG-DGG CY - Weimar, Germany DA - 29.05.2017 KW - Glass KW - Crack healing PY - 2017 AN - OPUS4-41347 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Blaeß, Carsten A1 - Müller, Ralf A1 - Thompson, Cyrus T1 - Crack healing in glass matrix composites N2 - Partially crystalline glasses are predominantly used as solid oxide fuel cell (SOFC) sealants due to their superior long term durability. However, cracks caused by thermal cycling still remain a substantial bottleneck in developing durable SOFC sealants inasmuch as, in contrast to crystal free glasses, large crystal volume fractions can retard healing. Hence, the basic understanding of crack healing in glassy crystalline materials and the effects of micro structure are important for finding optimum micro structures for both, durability and crack healing. For studying these effects, several model glass matrix composites (GMC), for which simultaneous crystal growth and crack healing can be excluded, have been synthesized. Sodium calcium silicate glass – zirconia GMC turned out to provide sufficiently homogeneous, dense and durable model GMC for our studies. The microstructure of this GMC shows large crystal free glassy regions embedded in network of finely dispersed ZrO2 nanoscale crystals. Whereas the glassy regions allow easy local crack healing, the network of dispersed crystals increases the effective viscosity on a global scale. This effect substantially retards crack broadening during later healing stages, which often ends up in large pores. Therefore, this type of microstructure seems to be an interesting candidate for crack healing optimized sealants. T2 - 91. Jahrestagung HVG-DGG CY - Weimar, Germany DA - 29.05.2017 KW - Glass KW - Crack healing KW - Glass ceramic KW - Composite PY - 2017 AN - OPUS4-41348 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Feldmann, Titus A1 - Fedelich, Bernard A1 - Epishin, Alexander A1 - Charmi, Amir T1 - Simulation of creep of a single crystal superalloy considering the transport of dislocations N2 - The investigation of creep behavior of the single crystal superalloy CMSX-4 at 1288°C is important for the understanding of deformations mechanisms under hot isostatic pressing (HIP). This treatment is used to increase the lifetime of single crystal superalloys by reducing the number of cavities. The understanding of the internal processes during this treatment is still limited due to the material being not single-phase at room temperature, the extreme conditions of HIP and the complexity of the material. The result of predicting the pore shrinkage rate using classical crystal plasticity was not satisfying. A more complex model has been implemented, now taking the heterogeneity of dislocation sources into account. By introducing a dislocation density, one can describe the transport, nucleation and interaction of dislocations. T2 - ICMM5 CY - Rome, Italy DA - 14.6.2017 KW - Einkristalllegierung KW - Kristallplastizität PY - 2017 AN - OPUS4-42036 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nguyen, Thi Yen A1 - Bernardes, C. E. S. A1 - Minas da Piedade, M. E. A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Guided crystallization: The influence of solvent and concentration N2 - Theoretical and experimental studies indicate that crystal nucleation can take more complex pathways than expected on the ground of the classical nucleation theory. A direct in situ observation of the different pathways of nucleation from solution is challenging since the paths can be influenced by heterogeneous nucleation sites, such as container walls. The custom-made acoustic levitator using in these experiments regulates the influence that solid surfaces, temperature, and humidity have on the crystallization process. The investigations of the crystallization process of paracetamol were performed with in situ analytical techniques and theoretical simulations to gain a comprehensive insight into processes, occurring intermediates, and required reaction conditions. The targeted choice of the solvent and the concentration enabled the guidance of the pathways, therefore, resulting in the isolation of one desired crystalline structure. T2 - Annual COST meeting CY - Lincoln, United Kingdom DA - 25.06.2017 KW - Crystallization KW - Polymorphism KW - Molecular dynamic simulation KW - Pair distribution function analysis KW - XRD PY - 2017 AN - OPUS4-41111 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Castro, R. A. E. A1 - Cortesao, A. M. A1 - Maria, T. M. R. A1 - Silva, M. R. A1 - Emmerling, Franziska A1 - Canotilho, J. A1 - Eusebio, M. E. S. T1 - New cocrystals of bexarotene with pyridinecarboxamide isomers sustained by the acid∙∙∙aromatic nitrogen supramolecular heterosynthon N2 - Pharmaceutical cocrystals are homogenous crystalline structures made up of two or more components in a definite stoichiometric ratio, where at least one of the components in the crystal lattice is an active pharmaceutical ingredient (API).1 Pharmaceutical cocrystals have opened the opportunity for engineering solid-state forms designed to have tailored properties to enhance drug product bioavailability and stability, as well a enhance processability of the solid material inputs in drug product manufacture. In this work the cocrystallization of bexarotene, an approved API by the U.S. Food and Drug Administration that belongs to Biopharmaceutics Classification System Class II (low solubility–high permeability), with pyridine carboxamide isomers (picolinamide, nicotinamide and isonicotinamide) was successfully undertaken. The synthesis was achieved by liquid assisted grinding (LAG) and the solids obtained were characterized by differential scanning calorimetry (DSC), infrared spectroscopy (FTIR-ATR), powder X-ray diffraction (XRPD), single crystal X-ray diffraction (SXD), and polarized light thermomicroscopy (PLTM). For bexarotene: picolinamide and bexarotene:isonicotinamide, 1:1 cocrystals were obtained directly from milling. SXD data of bexarotene:isonicotinamide cocrystal reveal acid∙∙∙aromatic nitrogen supramolecular heterosynthon and that the homosynthon amide∙∙∙amide in isonicotinamide is preserved. The bexarotene:nicotinamide mixtures prepared by ball milling give rise to simple binary solid–liquid phase diagram with an eutectic point, well described by the Schröder-van Laar equation. Melt crystallization of the 1:1 mixture gives rise to a cocrystal for which a complex phase behaviour is observed. T2 - 6th Meeting IAPC CY - Zagreb, Croatia DA - 04.09.2017 KW - Crystalline structure KW - Bexarotene KW - Powder X-ray diffraction KW - Single crystal X-ray diffraction KW - Infrared spectroscopy PY - 2017 AN - OPUS4-41063 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rosignuolo, F. A1 - Chaves Spoglianti de Souza, Roberto A1 - Andreini, M. A1 - La Mendola, S. A1 - Knaust, Christian T1 - A comparison between empirical models and FDS simulation to predict the ceiling gas temperature distribution in a tunnel fire N2 - A comparison between the results obtained from a Computational Fluid Dynamic (CFD) simulation and from the application of an empirical formula for determining the temperature distribution inside a tunnel in case of fire is presented. The temperature is measured and calculated at different distances from the location of the fire and at different time intervals. The fire considered varies with time following a time-heat release rate curve which has a parabolic growing phase, a constant period and a linear decay. The comparison reveals differences in the results. The temperatures calculated with the empirical formula resulted higher than the temperatures obtained by means of the CFD simulation. A list of possible reasons for this limited correspondence is also presented and commented. A proposal for further studies to better define the limitations of both the procedures and to define the influence of each parameter involved is finally presented. T2 - World Tunnel Congress 2017 – Surface challenges – Underground solutions CY - Bergen, Norway DA - 09.06.2017 KW - CFD KW - Fire KW - Tunnel KW - Design Fire PY - 2017 AN - OPUS4-40655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waurischk, Tina A1 - Balzer, R. A1 - Kiefer, P. A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Behrens, H. A1 - Deubener, J. T1 - New device for inert crack growth measurements in ultra-strong glasses N2 - The practical strength of glasses under ambient conditions is substantially lower compared to its intrinsic strength because of sub-critical crack growth (SCCG) from microscopic flaws. While SCCG is related to the humidity of the ambient atmosphere, leading to stress corrosion phenomena, the detailed kinetics are still not fully understood. To get better insight to the contribution of water on the crack-tip, highly water bearing glasses will be investigated by a new device for inert SCCG-measurements using double cantilever beam (DCB) geometry specimens. This device was designed to investigate the stress intensity factor in modus I and crack velocity in vacuum, but different atmospheres can also be introduced. For validation of the new device, first experiments were performed on microscope slides as well as on a soda-lime silicate and a borosilicate crown glass. The results achieved will be presented in comparison to the published results of Wiederhorn. T2 - 91. Glastechnische Tagung CY - Weimar, Germany DA - 29.05.2017 KW - Double cantilever beam KW - DCB KW - Crack intensity factor KW - Crack growth velocity KW - Glass PY - 2017 AN - OPUS4-40680 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Frenzel, Florian A1 - Würth, Christian A1 - Muhr, V. A1 - Hirsch, T. A1 - Resch-Genger, Ute T1 - Power dependent optical properties of hexagonal β-NaYF4: x % Er3+, 20 % Yb3+ core/ core-shell upconversion nanoparticles in cyclohexane and water N2 - Lanthanide doped photon upconverting nanophosphors (UCNPs) have the unique capability to produce narrow band, multi-color emission in the UV/vis/NIR upon multiphotonic absorption of infrared light, which makes them promising reporters for diagnostic, bioanalytical, and biological applications. This minimizes background signals, which normally occur due to autofluorescence from auxochromes, in biological matrices and enables deep penetration depths in biological applications. Moreover, UCNPs show long luminescence lifetimes in the μs range favorable for time gated emission in conjunction with a high photostability and chemical inertness and they do not blink. One of the most efficient upconversion (UC) phosphors for conversion of 976 nm to 655 nm and 545 nm light presents the hexagonal NaYF4-host crystal doped with 20 % Yb3+ used as sensitizer to absorb infrared light and 2 % Er3+ acting as activator mainly responsible for light emission. The high transparency in the relevant spectral windows of this host together with its low phonon frequencies ensure relatively high luminescence efficiencies. Although UCNPs are ideal candidates for many chemical and biological sensing and imaging applications, compared to other well-known chromophores like organic dyes or QDs, they suffer from a comparatively low brightness due to the low absorption cross sections of the parity forbidden f-f-transitions and low photoluminescence quantum yields (QYUC) particularly in the case of small nanoparticles with sizes of < 50 nm. The rational design of more efficient UCNPs requires an improved understanding of the nonradiative decay pathways in these materials that are influenced by particle architecture including dopant ion concentration and homogeneity of dopant distribution within UCNPs, size/surface-to-volume ratio, surface chemistry, and microenvironment. A promising approach to overcome the low efficiency of UCNPs is to use plasmonic interactions between a noble metal (Ag or Au) structure in the proximity of UCNPs and the incident light. This interaction leads to a modification of the spectroscopic properties due to local field enhancements and can involve an increase of the photoluminescence. In this respect, we study the interactions of UCNPs with metal structures (clusters and shells) by varying shape and size. Here, first results derived from integrating sphere spectroscopy and time-resolved fluorescence measurements are presented. T2 - Summer School "EXCITING NANOSTRUCTURES" CY - Bad Honnef, Germany DA - 17.07.2017 KW - Upconversion KW - Nanoparticle KW - Flourescence KW - Core-shell architecture KW - NIR KW - Absolute flourometry KW - Integrating sphere spectroscopy KW - Er(III) KW - Yb(III) KW - Single particle spectroscopy PY - 2017 AN - OPUS4-41172 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dhamo, Lorena A1 - Würth, Christian A1 - Raevskaya, A. E. A1 - Stroyuk, O. L. A1 - Gaponik, N. A1 - Eychmüller, A. A1 - Resch-Genger, Ute T1 - Syntheses and characterization of 2-4nm AgInS2/ZnS quantum dots N2 - Ternary semiconductors Quantum Dots (t-QDs) like AgInS (AIS) QDs are interesting alternatives to Cd-based QDs for applications as optical active materials in light-emitting diodes (LEDs), solar concentrators and solar cells as well as as biodiagnostic tools, respectively. AIS QDs exhibit broad photoluminescence (PL) spectra in the visible and near infrared, which are tunable by size and chemical composition (ratio of components or doping). In order to enhance the PL quantum yield (PL QY or Fpl) and prevent material deterioration and oxidation, these QDs are covered by ZnS shell. Here we show a spectroscopic study of differently colored AIS QDs synthesized in water, evaluating their PL properties, their PL QY and their PL decay. The simple aqueous synthesis that avoids further ligand exchange steps for bioanalytical applications, the tunable emission color, the high PL QY, the high absorption coefficients and the long lifetime make these t-QDs promising Cd-free materials as biodiagnostic tools or optical active materials. T2 - Summer School "EXCITING NANOSTRUCTURES" CY - Bad Honnef, Germany DA - 17.07.2017 KW - Semiconductor KW - Nanoparticle KW - Quantum dot KW - Flourescence KW - Synthesis KW - Spectral multiplexing KW - Ternary quantum dot PY - 2017 AN - OPUS4-41173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sentker, K. A1 - Yildirim, Arda A1 - Zantop, A. A1 - Lippmann, M. A1 - Hofmann, T. A1 - Seeck, O. A1 - Kityck, A. A1 - Mazza, M. A1 - Schönhals, Andreas A1 - Huber, P. T1 - Characterization of the thermotropic phase behavior and microscopic structure of a confined discotic liquid crystal N2 - Discotic liquid crystals (DLC) filled into cylindrical nanopores exhibit a liquid crystalline phase with their molecules arranged in hexagonal columns. The columns orient perpendicular (radially) or parallel (axially) with respect to the pore axis depending on surface anchoring conditions and pore size. Axially oriented columns enable the fabrication of organic nanowires utilizing the high conductivity in the stacking direction due to overlapping π-electrons. This leads to interesting applications in e.g. organic semiconductorbased devices. The molecular ordering of the liquid crystalline columns can be probed by temperature dependent optical retardation measurements supplemented by X-ray diffraction sensitive to the translational order. We investigated the DLC 2, 3, 6, 7, 10, 11 - hexakis [hexyloxy] triphenylene (HAT6) embedded in nanoporous alumina and silica membranes as function of the pore diameter (12 nm - 180 nm). Due to their hydrophilic nature porous membranes enforce face-on anchoring leading to a radial orientation. To obtain edge-on anchoring conditions, and thus favoring axial orientation, the silica membrane surface is chemically modified. The optical retardation measurements show that the columns orient radially in these membranes independent of the anchoring conditions. Interestingly, a quantized phase transition of each molecular layer is found indicated by a distinct increase of the optical orientation. Additionally, an axial orientation of HAT6 filled into alumina membranes with a pore diameter of 25 nm is achieved. A Landau-de Gennes ansatz semi-quantitatively describes the phase transition behavior observed. X-ray diffraction experiments performed at the 3rd generation synchrotron radiation source PETRA III at DESY giving detailed information about the translational order support these findings. Summarizing, this study shows the existence of a phase transition in the molecular range as well as the suitability of the membrane with 25 nm pores as a template for preparing organic nanowires. T2 - Liquids 2017 – 10th Liquid Matter Conference CY - Ljubljana, Slovenia DA - 17.07.2017 KW - Discotic Liquid Crystals PY - 2017 AN - OPUS4-41180 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weigert, Florian A1 - Guhrenz, C. A1 - Strelow, C. A1 - Gaponik, N. A1 - Eychmüller, A. A1 - Mews, A. A1 - Resch-Genger, Ute T1 - Probing the bright and dark fraction of core-shell CdSe nanocrystals with single particle spectroscopy N2 - "The optical properties of semiconductor nanocrystals (SCNC) are controlled by constituent material, particle size, and surface chemistry, specifically the number of dangling bonds favoring nonradiative deactivation. This can lead to a distribution of photoluminescence Quantum yields (PL QY) amongst the SCNC particles, i.e., mixtures of “bright” and “grey” or “dark” SCNCs. Particularly the number of absorbing, yet not emitting particles can have a significant effect on the PL quantum yield obtained in ensemble measurements, leading to ist underestimation. The “dark fraction” is not assessable in common ensemble measurements; it can be probed only on a single particle level using a confocal laser scanning microscope coupled with an AFM. Such a setup was used to study core‐shell CdSe SCNCs with different shells and surface chemistries. Special emphasis was dedicated to correlate brightness, blinking, dark fraction, and decay kinetics of the single SCNCs with the ensemble PL QY and the PL decay kinetics. The results of this study can help to identify new synthetic routes and surface modifications to colloidally and photochemically stable SCNCs with a PL QY of close to unity." T2 - Summer School "EXCITING NANOSTRUCTURES" CY - Bad Honnef, Germany DA - 17.07.2017 KW - Semiconductor KW - Nanoparticle KW - Quantum dot KW - Flourescence KW - CdSe KW - Shell KW - Surface chemistry KW - Single particle spectroscopy PY - 2017 AN - OPUS4-41192 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Makris, Ruben A1 - Bronsert, Jeffrey A1 - Hille, Falk A1 - Kirschberger, D. A1 - Sowietzki, D. T1 - Crack Luminescence as innovative method for detection of fatigue damage N2 - Conventional methods of crack detection only provide a snapshot of the fatigue evolution at a specific location and in the moment of examination. The crack luminescence method realizes a clear visibility of the occurring cracks in loaded components during ongoing operation. Several different experiments show that due to the sensitive coating even the early stage of the crack formation can be detected what makes the crack luminescence helpful to determine the incipient crack opening behavior depending on load alternation. Due to the emitting of light under UV-radiation the crack gets clearly visible what makes continuous monitoring and automated crack detection possible. This can reduce costs and time needed for maintenance and inspection. T2 - Sensor +Test 2017 CY - Nuremberg, Germany DA - 30.05.2017 KW - Fatigue damage KW - Crack KW - Luminescence KW - Detection PY - 2017 AN - OPUS4-41839 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babutzka, Martin A1 - Reinemann, Steffi A1 - Lehmann, Jens A1 - Burkert, Andreas T1 - Influence of corundum grinding processes on the corrosion behaviour of austenitic stainless steels N2 - The scientific poster shows by means of corrosion testing in combination with surface analytical methods to which degree corundum grinding influences the corrosion behaviour of stainless steel surfaces. The austenitic stainless steel AISI 304 from a consistent heat was used for all investigations to guarantee the same chemical composition and thus no additional influences caused by the material itself. A wide range of different grinding parameters such as pressure, cooling medium and grain size of the abrasive was varied. Thus, comparison of the corrosion behaviour of different surface states and the evaluation of an optimum grinding process using corundum abrasives were possible. The results will contribute to present discussions and give novel impulses for companies in the metalworking industry. T2 - Eurocorr 2017 CY - Prague, Czech Republic DA - 03.09.2017 KW - Korrosion KW - Corrosion KW - Korundschleifen KW - Corundum grinding KW - Nichtrostende Stähle KW - Stainless steels PY - 2017 AN - OPUS4-41896 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koerdt, Andrea T1 - Methanogene Archaea - The impact of methanogenic Archaea on material, environment and health N2 - Different environmental samples reveal that methanogenic Archaea are part of a multi-species biofilm on corroding metallic structures (Fig. 1). Studies on microbial influenced corrosion (MIC) focus mainly on sulphate reducing Bacteria (SRB), leading to the assumption that they are exclusively responsible for metal corrosion. In fact, methanogenic Archaea are known to be involved in metal corrosion as well (e.g. Methanococcus maripaludis DSM 2067). In some cases SRB and methanogenic Archaea have comparable high corrosion rates. However, the underlying mechanisms causing corrosion are still unknown. The goal of this study is to analyse two environmental isolates (M. maripaludis DSM 2067, M. maripaludis KA1) and two human-related isolates (Methanobrevibacter oralis and Methanobrevibacter smithii) for their ability to deteriorate/transform metals, which are relevant for technical and clinical applications. Moreover, the studies will provide essential information on the interaction mechanisms of human-related Archaea, which are frequently found in peri-implantitis, with dental material such as implants, crowns and bridges leading to their degradation/ transformation. T2 - EMBO-Course CY - Wageningen, The Netherlands DA - 24.07.2017 KW - Corrosion KW - Methanogens KW - Biofilm KW - Implants PY - 2017 AN - OPUS4-41899 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bertin, Annabelle A1 - Asadujjaman, Asad A1 - Ahmadi, Vahid T1 - Upper critical solution temperature (UCST)- type thermoresponsive polymers from acrylamide-based monomers N2 - UCST-type thermoresponsive polymers that phase separate from solution upon cooling present a tremendous potential not only in aqueous media where they can be used in drug delivery, diagnostic and microfluidic applications, but also in water/alcohol mixtures, where they can be used for instance in sensing systems for alcohol-soluble drugs. However, only a few thermoresponsive polymers have been reported that present an UCST in a relevant temperature range and “green” solvents such as water or ethanol. In this context, acrylamide-based monomers can be very useful building blocks for designing novel UCST-type polymers because of their hydrophilic nature (with the right side chain) and propensity to form hydrogen bonds. We want to present our latest results on the copolymer poly(acrylamide-co-acrylonitrile) (P(AAm-co-AN)) that present a UCST in water as well as on two homopolymers based on an acrylamide derivative of 2,6-diaminopyridine, namely poly(N-(6-aminopyridin-2-yl)acrylamide) (PNAPAAm) and poly(N-(6-acetamidopyridin-2-yl)acrylamide) (PNAcAPAAm) that show UCST-type thermoresponsiveness in water/alcohol mixtures. Our focus for P(AAm-co-AN)) is its aggregation behaviour above and below its phase transition temperature as the size of thermoresponsive polymeric systems is of prime importance for biomedical applications (as size dependent processes take place in the body) and is linked to the optical properties of a material that matter in materials science. In the case of PNAPAAm and PNAcAPAAm, we focused on the co-solvency/co-non solvency effect on the phase transition temperature in water/alcohol mixture. Indeed, polymers with UCST behavior below 60°C in water/alcohol mixtures are extremely promising for the preparation of “smart” materials for sensing. T2 - 31st Conference of the European Colloid and Interface Society (ECIS 2017) CY - Madrid, Spain DA - 03.09.2017 KW - Thermoresponsive polymers KW - UCST polymers KW - Acrylamide based polymers PY - 2017 AN - OPUS4-41902 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Erdmann, Maren A1 - Wachtendorf, Volker A1 - Sameith, Janin A1 - Niebergall, Ute A1 - Böhning, Martin T1 - Effect of surface degradation on high-density polyethylene for initial attachment of bacillus and pseudomonas N2 - High-density polyethylene (PE-HD) is a widely applied plastic for fuel storage tank applications. But such tanks, filled with diesel or biodiesel, provide excellent environmental conditions for growth of a broad spectrum of fungi and various bacteria1. This can result in fuel contamination, engine plugging or possible (bio-) degradation2. Our research focusses on the initial attachment phase of Bacillus sp. and Pseudomonas aeruginosa isolated from a „dieselpest“2 on two distinctly PE-HD materials, typical for fuel storage tank applications, pre-damaged thermally and by UV-irradiation. T2 - PDDG CY - Taormina, Sicily, Italy DA - 04.09.2017 KW - PE-HD KW - UV-irradiation KW - Initial attachment KW - Bacteria PY - 2017 AN - OPUS4-41908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Erdmann, Maren A1 - Niebergall, Ute A1 - Böhning, Martin T1 - Long-term storage of high-density polyethylene in biodiesel and diesel fuels N2 - Sustainable energy and clean engine fuels receive more and more attention. Petrodiesel could be substituted by biofuels such as biodiesel produced from renewable resources. Biodiesel is derived by transesterification of oils with alcohols for example vegetable oils, animal fats or food waste. Its chemical composition of unsaturated fatty methyl acids causes biodiesels susceptibility to oxidation. Especially, the polymer-biodiesel performance under long-term conditions has been considered only in few researches. Our study addresses a long-term storage scenario of a polymeric fuel tank containing biodiesel or diesel. T2 - PDDG CY - Taormina, Sicily, Italy DA - 04.09.2017 KW - PE-HD KW - Degradation KW - Biodiesel KW - Diesel PY - 2017 AN - OPUS4-41909 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Thoralf A1 - Lehmann, Jens A1 - Burkert, Andreas T1 - Long term corrosion behavior of stainless steel in maritime atmosphere N2 - In the context of a research project carried out by BAM, nine different steel alloys were exposed to maritime environmental conditions at the German Island of Helgoland over a period of five years and their corrosion behavior was compared and evaluated. In order to evaluate the influence of a possible concentration of corrosion specific crucial air constituents on the investigated steel grades, a series of sample surfaces were freely exposed to the we ather while other samples were protected from direct rain in a covered area. The parallel investigation of four different surface finishes (cold rolled, dry grinded, electro-polished, blasted) of the respective alloys also made it possible to take account of the specific influences and features of the surface finish during the material comparison. On the basis of the results of the natural exposure tests, conclusions were drawn about the influence of the alloy composition, the surface finish and the exposure time under maritime conditions. The samples of the three investigated duplex alloys exhibited the best corrosion resistance under the given maritime environmental conditions over the five-year period, both with and without crevice geometry. Likewise, the molybdenum alloy ferrite 1.4521 could achieve comparable corrosion resistance as the austenitic standard materials 1.4301 and 1.4404. The results on the freely exposed surfaces showed, that due to the washing effect the influence of the exposure time on the corrosion of the samples is low while the particular surface finish has a great influence on the overall corrosion behavior of the stainless steels. Thus, the electro-polished surfaces showed few signs of corrosion while the blasted surfaces exhibited very poor corrosion behavior. In the case of the covered specimens, the respective material-specific corrosion resistance as well as the exposure time have a significant influence on the corrosion behavior while the surface finishes were of marginal importance. T2 - EuroCorr 2017 CY - Prague, Czech Republic DA - 03.09.2017 KW - Corrosion KW - Maritime atmosphere KW - Stainless steel PY - 2017 AN - OPUS4-41859 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Thoralf A1 - Rosemann, Paul T1 - Influence of the post-weld surface treatment on the corrosion resistance of duplex stainless steel 1.4062 N2 - The duplex stainless steel 1.4062 (X2CrNiN22-2) is used as alternative material to austenitic stainless steels in the construction industry. The corrosion resistance of welded seams is influenced by the base material, the weld filler material, the welding process and also by the final surface treatment. The scale layer next to the weld seam can be removed by grinding, pickling, electro-polishing or blasting depending on the requested corrosion resistance. Blasted surfaces are often used in the industrial practice due to the faster and cheaper manufacturing process compared to pickled or electro-polished surfaces. Furthermore blasting with corundum-grain is more effective than blasting with glass-beads which also lower the process costs. In recent years, stainless steel surfaces showed an unusually high susceptibility to pitting corrosion after grinding with corundum. For this reason, it is now also questioned critically whether the corrosion resistance is influenced by the applied blasting agent. This question was specifically investigated by comparing grinded, pickled, corundum-grain- and glass-bead-blasted welding seams. Results of the SEM analyses of the blasting agents and the blasted surfaces will be presented and correlated with the results of different corrosion tests (KorroPad-testing and pitting potentials). T2 - Eurocorr 2017 CY - Prague, Czech Republic DA - 03.09.2017 KW - Duplexstahl KW - Korrosion KW - Nichtrostender Stahl KW - Oberflächenbearbeitung KW - Schweißen KW - Strahlen PY - 2017 AN - OPUS4-41915 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gottlieb, Cassian A1 - Günther, Tobias A1 - Wilsch, Gerd T1 - Material properties and their impact on laserinduced plasmas for concrete analysis N2 - For concrete production aggregates, cement and water are mixed together and after 28 days of hydration a porous and multiphase material is formed. To consider the heterogeneity of concrete a 2D scanning system is used. The coarse aggregates (limit > 2 X d ) can be excluded. laser spot The remaining content is a mixture of flour grains and cement particles (micro heterogeneity). Harmful species like chlorides may penetrate together with water through the capillary pore space. A quantification of Cl regarding to the cement content only (European standard EN 206) is necessary for the damage assessment. A LIBS system operating with a NdCr:YAG laser (pulse energy of 3 mJ, a wavelength of 1064 nm, a pulse width of 1.5 ns, a repetition rate of 100 Hz) and two Czerny-Turner spectrometer (UV and NIR range) have been used. T2 - EMSLIBS Konferenz 2017 CY - Pisa, Italy DA - 12.06.2017 KW - Concrete KW - LIBS KW - Micro-heterogeneity PY - 2017 AN - OPUS4-40938 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Neumann, Martin A1 - Eisenacher, Germar A1 - Schönfelder, Thorsten A1 - Wille, Frank T1 - Development of a material model for the crush of spruce wood N2 - Typical transport packages used in Germany are equipped with wooden impact limiting devices. In this paper we give an overview of the latest status regarding the development of a finite element material model for the crush of spruce wood. Although the crush of wood – mainly in longitudinal direction – is a phenomenon governed by macroscopic fracture and failure of wood fibres we smear fracture and failure mechanisms over the continuous voume. In first step we altered an existing LS-DYNA material model for foams, which considers an ellipse shaped yield surface written in terms of the first two stress invariants. The evolution of the yield surface in the existing model depends on the volumetric strain only. For the use with spruce wood, we modified the existing material model to consider the deviatoric strain for the evolution of the yield surface as well. This is in accordance with the results of crush tests with spruce wood specimens, where the crushing deformation was rather deviatoric for uniaxial stress states and rather volumetric for multiaxial stress states We rate the basic idea of this approach to be reasonable, though other problems exist regarding the shape of the yield surface and the assumption of isotropic material properties. Therefore we developed a new transversal isotropic material model with two main directions, which considers different yield curves according to the multiaxiality of the stress state via a multi-surface yield criterion and a non-associated flow rule. The results show the ability to reproduce the basic strength characteristics of spruce wood. Nevertheless, problems with regularization etc. show that additional investigations are necessary. T2 - ASME PVP 2017 CY - Waikaloa, HY, USA DA - 16.07.2017 KW - Crush KW - Wood KW - Spruce KW - FEM PY - 2017 AN - OPUS4-41617 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Agudo Jácome, Leonardo A1 - Mosquera Feijoo, Maria A1 - Nolze, Gert A1 - Rizzo, F. T1 - Nano-sized precipitates in an Fe-13Cr alloy formed under oxidizing water vapor atmosphere N2 - Oxidation of a Fe-13Cr alloy under water vapor at 600 °C produced a zone of nano-sized precipitation underneath the outside scale formed by iron oxides and Fe‒Cr spinel. The majority of the spinel layer shows a mixed orientation relationship to the ferritic matrix {100}α || {100}sp & <011>α || <001>sp. However, also the discovered precipitated particles are characterized by the same crystallographic orientation relationship to the respective ferritic parent grain. The habit of the precipitates is best described by a lath morphology with their main axis parallel to <100> of ferrite. Energy dispersive X-ray spectroscopy (EDX) and electron backscatter diffraction (EBSD) in an scanning electron microscope (SEM) have been applied to characterize the oxide layer in the micrometer scale. The clearly smaller precipitates were subsequently investigated by transmission electron microscopy (TEM). Specimens have been prepared by focused ion-beam (FIB) milling at an area previously characterized by EBSD. They cover the ferritic base material, but mainly the precipitation zone and the Fe‒Cr spinel layer. Energy filtered selected area diffraction (SAD) in the conventional (C)TEM and high-angle annular darkfield (HAADF) imaging in the scanning (S)TEM mode were employed in the characterization of the specimens. T2 - International Conference on Solid-Solid Phase Transformations in Inorganic Materials (PTM) 2015 CY - Whistler, British Columbia, Canada DA - 28.06.2015 KW - Precipitation KW - Oxidation KW - Microscopy KW - Topotactic transformation KW - Spinel PY - 2015 AN - OPUS4-42169 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rizzo, F. A1 - Agudo Jácome, Leonardo A1 - Mosquera Feijoo, Maria A1 - Nolze, Gert A1 - Kranzmann, Axel A1 - Costa e Silva, A. T1 - Evaluation of nano-sized internal oxidation in a Fe-13Cr alloy exposed to water vapor atmosphere N2 - The topotactic formation of nano-sized precipitates immediately under the internal oxide layer in a Fe-13Cr alloy exposed to oxidizing water vapor atmosphere was recently reported. The precipitates were identified as lath-shaped Fe-Cr spinel exhibiting a crystallographic orientation relationship with the ferritic matrix. The authors proposed that these precipitates could act as a precursor to the formation of the spinel layer observed in the adjacent part of the oxide scale.The occurrence of internal oxidation in Fe–Cr alloys subjected to similar conditions had been previously identified and directly correlated to the presence of water vapor. In the present work, we attempt to rationalize the processes occurring during the oxidation of this alloy through thermodynamic and kinetic analyses based on the CALPHAD approach, using the geometrical representation of phase equilibria and concepts developed to describe internal oxidation. The influence of water vapor on the mechanism and kinetics of formation of the nano-sized precipitates and its role in the overall oxidation process is also considered. T2 - CALPHAD XLV The forty-fifth International Conference on CALPHAD (Computer Coupling of Phase Diagrams and Thermochemistry) CY - Awaji Island, Hyogo, Japan DA - 29.05.2016 KW - Precipitation KW - Internal oxidation KW - CALPHAD KW - Topotactic transformation KW - Microscopy PY - 2016 AN - OPUS4-42156 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wolter, Christian A1 - Gradt, Thomas T1 - Metallsulfide als Reibungsstabilisatoren in Bremsbelägen - tribologische Untersuchungen an Modellsystemen N2 - Der Posterbeitrag handelt davon, wie das Reibverhalten und die Temperaturabhängikgeit durch den Einsatz von Metallsulfiden maßgeblich beeinflusst wird und zur Stabilität beiträgt. T2 - 59. Tribologie-Fachtagung CY - Goettingen, Germany DA - 24.09.2018 KW - Metallsulfide KW - Bremsbeläge KW - Tribologie PY - 2018 AN - OPUS4-46187 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rockenhäuser, Christian A1 - Skrotzki, Birgit T1 - The long-term ageing process of alloy 2618A N2 - The long-term ageing process of alloy 2618A was introduced and discussed The dark-field transmission electronmicroscopical resilts werde shown and evaluated regarding the precipitate radii. The influence of the precipitate radii regarding ageing was used for a preliminary ageing assessment. T2 - 19th International Microscopy Congress (IMC19) CY - Sydney, Australia DA - 09.09.2018 KW - Alloy 2618A KW - Degradation KW - Coarsening KW - S-phase KW - Dark-field transmission electron microscopy (DFTEM) PY - 2018 AN - OPUS4-46123 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Haferkamp, Sebastian A1 - Akhmetova, Irina A1 - Kulla, Hannes A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Mechanochemical Knoevenagel condensations of benzaldehyde derivates investigated in situ N2 - Mechanochemistry is widely applicable for the synthesis of inorganic, metal-organic, and organic compounds. It is known for short reaction times, nearly quantitative conversions, and decreasing amount of solvents, which opens the field to more environmentally friendly syntheses routes. Among organic syntheses, the Knoevenagel condensation is an important C-C bond forming reaction leading to α,β-unsaturated compounds. To gain more information on the underlying processes, we investigated the syntheses by a combination of different in situ investigation techniques, including synchrotron X-ray diffraction, Raman spectroscopy and thermography. This combination provides information on the structural changes and temperature influences during milling. Benzaldehyde derivates (nitro- and fluoro-derivates) reacted with malononitrile to the respective benzylidenemalononitriles. The in situ investigations show direct and quantitative conversions. In the case of the fluorinated benzaldehyde derivates we showed the possibility of using liquid substrates in mechanochemical organic synthesis. Surprisingly, after crystallization from a viscous state, the material was suitable for single-crystal X-ray analysis. T2 - Powder Diffraction School 2018 CY - Villigen, Switzerland DA - 24.09.2018 KW - C-C coupling KW - Mechanochemistry KW - In situ KW - Knoevenagel PY - 2018 AN - OPUS4-46320 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stroh, Julia A1 - Emmerling, Franziska T1 - In situ full phase analysis of the early cement hydration N2 - Fresh cement paste is a suspension consisting of a hydraulic binder (cement), water, and numerous minor components – admixtures. Addition of admixtures aims at specific modification of properties of the fresh cement paste or hardened cementitious building material. Specific admixtures, so-called superplasticizers (SP), are used to improve the flowability of the fresh cement paste with reduced water content. The latter is the starting material for the high-strength concrete. Thus, SPs are essential for the ambitious construction projects. However, uncontrollable retardation of the setting time in presence of SPs is occasionally observed. Obviously, SPs influence early products of the cement hydration leading to changes in the microstructure development. The hardening is thus delayed, and the quality of the resulting building material suffers. The mechanisms of the admixture action during the hydration process are still intensively investigated [1-7]. A detailed understanding of the admixture effects during the early hydration stage is the key to control and individual adjustment of the cement-based construction materials. We use the unique combination of the wall-free sample holder and the time-resolved X-ray scattering analysis to achieve the full information about the hydrate phases formed under the influence of admixtures. We use ultrasonic levitator to start the cement hydration in levitated cement pellets [8, 9]. The sample levitation allows collection of the unimpaired information about cement hydrate phases. The most beneficial is the avoiding of the contributions of the sample holder material to the data signal. We induce the cement hydration by adding water to unhydrated Portland cement during the data acquisition. The full phase composition of the hydrating cementitious system can be gathered in situ using wide angle X-ray scattering (WAXS). During the hydration of cement both crystalline and amorphous hydrate phases are formed. WAXS data contain the information about crystalline phases behind the Bragg reflections, whereas the amorphous hydrates influence the appearance of the background. Application of the data analysis specific for crystalline or amorphous phases is needed. The data quantification by the Rietveld method allows to conclude about the changes of the phase amounts due to the presence of admixture. The calculation of the pair distribution functions allows analysis of the amorphous hydrates. Based on this information, the SP effects and the extent of their involvement into the ongoing reactions can be concluded. A detailed understanding of the complex cement hydration process is envisioned. T2 - Anakon 2019 CY - Münster, Germany DA - 25.03.2019 KW - Cement KW - Admixtures KW - Pair Distribution Functions KW - X-ray diffraction KW - Total scattering analysis PY - 2019 AN - OPUS4-47664 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -