TY - CONF A1 - Kabelitz, Anke T1 - Time-resolved studies on the formation of maghemite nanoparticles combining fast-XANES and SAXS N2 - Iron oxide nanoparticles find application in different areas like sensing, magnetic storage media, and biomedicine, due to their magnetic properties and environment-friendliness. In the present contribution, we report on the in situ investigation of an iron oxide nanoparticle synthesis by coupled X-ray absorption near-edge structure (XANES) and small-angle X-ray scattering (SAXS). The combination provides simultaneously information about the size of particles (SAXS) and on the oxidation state and the local structure of the iron atoms (XANES). The co-precipitation synthesis was exemplary studied, using a stabilization agent to decelerate the fast precipitation of the iron oxides. This allows to detect intermediates in situ. The measurements were performed using a custom-made acoustic levitator as sample holder. From the data, a mechanism was derived indicating different phases of particle Formation and oxidation state changes. T2 - The European Materials Research Society-Spring Meeting 2016 CY - Lille, France DA - 01.05.2016 KW - Iron oxide nanoparticles KW - SAXS KW - XANES KW - Time-resolved PY - 2016 AN - OPUS4-36351 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kathan, Michael T1 - Photocontrolling imine exchange kinetics to modulate inherent characteristics of self-healing polysiloxane networks N2 - Materials that respond to the environment by changing their properties are critical for developing autonomously adaptive systems. However, to reversibly influence a material's inherent characteristics, such as its ability to self-heal, from distance without continuously expending energy, remains a challenging task. Herein, we report on the modul at ion of imine exchange kinetics by light, manifested in a remote controllable dynamic covalent polymer network. Simple mixing of a commercially available amino-functionalized polysiloxane with small amounts of a photoswitchable diarylethene cross-linker, carrying two aldehyde groups, yields a rubbery material. Its viscoelastic and self-healing properties can be reversibly tuned with everyday light sources, such as sunlight. Our two-component system offers the unique advantage that self-healing takes place continuously without any additives at ambient conditions and is neither dependent on continuous illumination nor does it require recent damage. Overall, our approach allows for the local amplification of intrinsic material properties in a permanent yet reversible fashion. The availability of the inexpensive sta1ting materials on a multi-gram scale, the easy synthesis of the polymer network, and its convenient handling paired with high versatility make our Approach highly applicable to create custom-tailored adaptive materials. T2 - POLYDAYS 2016 CY - Potsdam, Germany DA - 28.09.2016 KW - Self-healing KW - Polymer PY - 2016 AN - OPUS4-37623 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Influence of Experimental Conditions and Calculation Method on Hydrogen Diffusion Coefficient Evaluation at Elevated Temperatures N2 - Hydrogen-assisted cracking (HAC) represents a significant failure risk for (high strength) creep resistant low-alloyed steel components in fossil-fired power plant applications at temperatures of up to and above 200 °C. This particularly applies to respective start-up and shut-down processes associated with alternating service-conditions in terms of load flexible power plants. For quantitative determination of localized crack critical hydrogen concentrations, the temperature dependent hydrogen diffusion coefficients have to be determined as exactly as possible. However, available literature provides a wide range of hydrogen diffusion coefficients for low alloyed steels with similar microstructures. Additionally, the available diffusion data seem not to be very reliable and their scatter increases with decreasing temperature. One reason is that the experimental boundary conditions can have a major impact on the determination of respective effective diffusion coefficients. Hence, the scope of this study is to evaluate the influence of the experimental boundary conditions on the derived diffusion coefficients. In addition, different methods for calculating diffusion coefficients are discussed. To elucidate such influences and to draw a line to practical application, the diffusion and trapping behavior in the creep resistant steel 7CrMoVTiB10 10 has been studied. For such purpose, hydrogen charged specimens were isothermally degassed at different temperatures using carrier gas hot extraction (CGHE). Based on experimental data, a numerical model has been developed by which the hydrogen transport behavior and the respective hydrogen distribution during CGHE can be assessed. It is demonstrated that the specimen heating rate has a large influence on the calculated diffusion coefficients under assumption of isothermal degassing which elsewhere has been underestimated in the assessment of diffusion data in creep-resistant steels. The numerical results suggest that calculation methods for diffusion coefficients are limited if compared to experimental results. It also turned out that the sample preparation time before CGHE can enormously influence determined diffusion coefficients. Consequently, non-homogeneous hydrogen concentration profiles have to be anticipated in the simulations to arrive at characteristic effusion curves consistent to respective CGHE experiments. In turn, validated diffusion coefficients are now available for the low-alloyed Cr-Mo-V steel, which can be helpful to calculate appropriate hydrogen removal heat treatment procedures. T2 - Project Meeting CAStLE CY - Colorado Springs, CO, USA DA - 07.09.2016 KW - Hydrogen KW - Diffusion Coefficient KW - Elevated Temperatures KW - Numerical Modeling KW - Carrier Gas Hot Extraction PY - 2016 AN - OPUS4-37408 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Butz, Adam T1 - Experimental and analytical investigation of notched components of a Nickel based superalloy under high temperature cyclic loading N2 - While the increase in use of renewable energy sources is a necessity in times of climate change the use of gas turbines as back-up requires them to be run in a much more flexible manner in order to compensate for side effects like sudden fluctuations of energy generation. The significant changes of stress and temperature levels in turbine blades due to start-up and shut down can cause crack initiation and growth in the blades‘ alloy. The aim of this research project is to identify a model for lifetime prediction for gas turbine components made of a Nickel base superalloy under high temperature with a Focus on stress concentration points such as cooling holes. T2 - HIDA-7 Conference on Life/Crack Assessment & Failures in Industrial Structures, UK CY - Portsmouth, UK DA - 15.05.2017 KW - LCF KW - Gas turbine KW - Service life model PY - 2017 AN - OPUS4-42274 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Influence of experimental conditions and calculation method on hydrogen diffusion coefficient evaluation at elevated temperatures N2 - Hydrogen-assisted cracking (HAC) represents a significant failure risk for (high strength) creep resistant low-alloyed steel components in fossil-fired power plant applications at temperatures of up to and above 200 °C. This particularly applies to respective start-up and shut-down processes associated with alternating service-conditions in terms of load flexible power plants. For quantitative determination of localized crack critical hydrogen concentrations, the temperature dependent hydrogen diffusion coefficients have to be determined as exactly as possible. However, available literature provides a wide range of hydrogen diffusion coefficients for low alloyed steels with similar microstructures. Additionally, the available diffusion data seem not to be very reliable and their scatter increases with decreasing temperature. One reason is that the experimental boundary conditions can have a major impact on the determination of respective effective diffusion coefficients. Hence, the scope of this study is to evaluate the influence of the experimental boundary conditions on the derived diffusion coefficients. In addition, different methods for calculating diffusion coefficients are discussed. To elucidate such influences and to draw a line to practical application, the diffusion and trapping behavior in the creep resistant steel 7CrMoVTiB10 10 has been studied. For such purpose, hydrogen charged specimens were isothermally degassed at different temperatures using carrier gas hot extraction (CGHE). Based on experimental data, a numerical model has been developed by which the hydrogen transport behavior and the respective hydrogen distribution during CGHE can be assessed. It is demonstrated that the specimen heating rate has a large influence on the calculated diffusion coefficients under assumption of isothermal degassing which elsewhere has been underestimated in the assessment of diffusion data in creep-resistant steels. The numerical results suggest that calculation methods for diffusion coefficients are limited if compared to experimental results. It also turned out that the sample preparation time before CGHE can enormously influence determined diffusion coefficients. Consequently, non-homogeneous hydrogen concentration profiles have to be anticipated in the simulations to arrive at characteristic effusion curves consistent to respective CGHE experiments. In turn, validated diffusion coefficients are now available for the low-alloyed Cr-Mo-V steel which might be helpful to calculate appropriate hydrogen removal heat treatment procedures, for instance. T2 - International Hydrogen Conference - Material Performance in Hydrogen Environments CY - Jackson Lake Lodge, Moran, Wyoming, USA DA - 11.09.2016 KW - Hydrogen diffusion KW - Elevated temperatures KW - Welding KW - Creep-resistant steel KW - Numerical modeling KW - Calculation PY - 2016 AN - OPUS4-37403 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded T1 - Sputtering derived artefacts in austenitic steel during Time-of-Flight Secondary Ion Mass Spectrometry analyses N2 - Among the very few techniques to localize hydrogen (H) at the microscale in steels, Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was proven to be a reliable tool. The necessity to detect hydrogen stems from its deleterious effects in metals, that are often used as structural components and to obtain better understanding of the underlying metallurgical mechanisms of hydrogen embrittlement (HE) which are still unclear. Austenitic stainless steels are nowadays commonly used in a wide variety of application, from hydrogen transport and storage facilities to petrochemical and offshore applications where they are exposed to aggressive environments and therefore prone to HE. One of the greater risks in the austenitic class is the embrittlement of the material due to the instability of the γ austenite and its transformation into a brittle α martensitic phase. This transformation takes place due to the local stresses that are induced by the uptake of hydrogen during service. Nonetheless, it was shown that this transformation can occur as an artefact during SIMS analysis itself where Cs-sputtering is necessary not only to remove surface contaminations but mainly to enhance H/D secondary ion yield. In the following contribution we show the influence of different sputtering conditions on AISI 304L austenitic stainless steel in order to distinguish the artefact from the hydrogen induced transformation. The material was charged electrochemically in a deuterium based electrolyte. Deuterium (D) must be in these experiments as a replacement for hydrogen which cannot be used because adsorbed hydrogen superimposes hydrogen originating from charging the sample in the SIMS images. ToF-SIMS analyses were conducted by ToF SIMS IV (IONTOF GmbH, Münster, Germany). The experiments were carried out on deuterium charged and non-charged samples. The structural characterization was carried out by SEM and EBSD examinations before and after charging, both with a Leo Gemeni 1530VP field-emission scanning electron microscope and a Zeiss Supra 40 instrument (Carl Zeiss Microscopy GmbH, Oberkochen, Germany). The results showed that the use of 1keV Cs+ beam induces stacking faults while higher sputter beam energies results in γ→α transformation. T2 - SIMS Europe 2018 CY - Münster, Germany DA - 16.09.2018 KW - Austenitic steel KW - Hydrogen KW - ToF-SIMS KW - Artefact PY - 2018 AN - OPUS4-46701 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten T1 - Entwicklung eines selbstverdichtenden Betons mit inerten Zusatzstoffen-Prüfung nach europäischer Richtlinie für SVB N2 - Im Rahmen von MICROCON, einem europäischen CRAFT-Projekt, besteht eine wesentliche Zielsetzung in der Optimierung von selbstverdichtendem Beton (SVB) im Hinblick auf Kosten und Leistungsfähigkeit durch den Einsatz von teilweise puzzolanischen Microfillern. Um die Puzzolanität bei der Beurteilung besser bewerten zu können, wird ein Referenzbeton benötigt, der aus weitestgehend inerten Zusatzstoffen besteht. Die Entwicklung eines solchen Referenzbetons fand an der BAM nach der japanischen Methode nach Okamura statt. T2 - Wissenschaftsrat CY - Berlin, Germany DA - 17.02.2006 PY - 2006 AN - OPUS4-12030 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Standardised Measurements of Surface Functionalities on Nanoparticles N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage which improve the quality of life and European prosperity. NP function, performance, interaction with biological species, and environmental fate are largely determined by their surface functionalities. Standardized repeatable surface characterization methods are therefore vital for quality control of NPs, and to meet increasing concerns regarding their safety. Therefore, industry, regulatory agencies, and policymakers need validated traceable measurement methods and reference materials. This calls for fit-for-purpose, validated, and standardized methods, and reference data and materials on the surface chemistry of engineered NPs. Here, we present a concept for the development of such standardized measurement protocols utilizing method cross-validation and interlaboratory comparisons (ILCs) with emphasis on both advanced measurement methods such as quantitative Nuclear Magnetic Resonance (qNMR), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) and cost-efficient, non-surface specific methods like optical assays and electrochemical titration methods. T2 - European Partnership on Metrology 2023 Review Conference CY - Amsterdam, Netherlands DA - 07.11.2023 KW - Surface chemistry KW - Quality assurance KW - Traceability PY - 2023 AN - OPUS4-59142 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scholtz, Lena T1 - Standardized Measurements of Surface Functionalities on Nanoparticles N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely and commonly fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage. NP function, their interaction with biological species, and also their environmental fate are largely determined by the surface functionalities of the particles. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, determination of their applicability, and mandatory to meet increasing concerns regarding their safety. In addition, industry as well as international standardization organizations, regulatory agencies, and policymakers need validated and standardized measurement methods and reference materials. However, methodologies for determining NP surface properties, including the amount, chemical composition, and homogeneity of surface functionalities and coatings are largely non-standardized up until now. Suitable methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques such as traceable quantitative nuclear magnetic resonance (qNMR), as well as X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods. The latter, typically less costly methods are often used by SMEs, e.g., for quality control. To validate methods, establish measurement uncertainties, test reference materials, and produce reference data, international interlaboratory comparisons (ILC) on NP surface functionalization measurements are required to provide well characterized test and reference nanomaterials including benchmark values.[1] These needs are addressed by the current European metrology project SMURFnano, involving 12 partners from different National Metrology Institutes, designated and research institutes, two university groups as well as one large company and one SME producing NPs. This project, as well as first results derived from the development of test and reference materials with a well characterized surface chemistry, and ongoing interlaboratory comparisons, will be presented. T2 - eMRS - Fall Meeting 2025 CY - Warsaw, Poland DA - 15.09.2025 KW - Nano KW - Particle KW - Silica KW - Polymer KW - Metrology KW - Quality assurance KW - Reference material KW - Surface chemistry KW - Size KW - Shape KW - Particle number concentration KW - Method KW - Optical assay KW - qNMR KW - Validation KW - Potentiometry KW - XPS PY - 2025 AN - OPUS4-64243 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brinkmann, A. T1 - A qNMR Method for Quantification of Surface Functional Groups on Silica Nanoparticles: Bilateral Comparisons N2 - Nanomaterials (NM) of different size, shape, morphology, composition, and surface chemistry are used in a wide range of applications, including medical diagnostics, and imaging and consumer products. The importance of an adequate and reliable characterization is crucial for quality control during NM production, for ensuring an optimum function for the desired application, and for risk assessment studies. Currently there is a lack of reliable and validated methods and reference materials for quantifying NM surface functional groups, despite the importance of surface chemistry for the production of colloidally stable materials, further processing steps, and the interaction with the environment and biological species. Following our initial study on the use of qNMR for quantifying the amount of amino groups on surface modified silica (1), we have carried out two bilateral comparisons between NRC and BAM to further develop and optimize a reliable protocol for these measurements (2,3), using aminated silica nanoparticles prepared by multiple methods, both commercial and in-house synthesized, and with varying amine content. Solution qNMR is based on dissolving aminated silica nanoparticles in strong base to release the surface grafted amino silane molecules, followed by the quantification of these molecules by solution qNMR using an internal standard. This method provides the amount of total amino groups present in the sample, which can differ from probe accessible or surface-sensitive measurements performed with X-Ray photoelectron spectroscopy (XPS). Complementary measurements using optical assays, involving a labeling step with a dye reporter, and XPS are employed to assess the probe accessible and surface amine content for representative samples. These measurements, which illustrate the advantages and potential limitations of the different characterization methods, will contribute to establish a basis for testing the protocol in an international inter-laboratory comparison and for standardization at ISO Technical Committee 229 – Nanotechnologies. T2 - BERM CY - Halifax, Canada DA - 01.06.2025 KW - Quality assurance KW - Nano KW - Particle KW - Synthesis KW - Advanced materials KW - Characterization KW - Electron microscopy KW - Silica KW - Surface KW - qNMR KW - Optical assay KW - Interlaboratory comparison KW - Metrology KW - Standardization PY - 2025 AN - OPUS4-63527 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -