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- Thermal Energy Storage (2)
- Alkali oxides (1)
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- Concentrated Solar Power (1)
- Copper Alloy (1)
- Data Space (1)
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Organisationseinheit der BAM
- 5 Werkstofftechnik (3)
- 5.1 Mikrostruktur Design und Degradation (2)
- 4 Material und Umwelt (1)
- 4.4 Thermochemische Reststoffbehandlung und Wertstoffrückgewinnung (1)
- 5.2 Metallische Hochtemperaturwerkstoffe (1)
- 6 Materialchemie (1)
- 6.5 Synthese und Streuverfahren nanostrukturierter Materialien (1)
- 7 Bauwerkssicherheit (1)
- 7.2 Ingenieurbau (1)
Large oligo-crystalline or single-crystalline metallic materials are of great interest for numerous applications, and a recently developed strategy for promoting abnormal grain growth induced by a cyclic heat treatment opens up new opportunities to manufacture single crystals with a size of several centimeters. So far, the entire available knowledge on this kind of abnormal grain growth has been elaborated based on time discrete observations and, thus, detailed insights into the interplay of elementary mechanisms are still lacking in open literature. The present study reveals time resolved insights into this kind of abnormal grain growth for the first time. It was possible to break down the influence of the individual heat treatment phases by in situ synchrotron high energy X-ray diffraction analysis during cyclic heat reatment. The results obtained not only help to gain a deep understanding of the abnormal grain growth mechanisms, they will also be the basis for an adjustment of the cyclic heat treatment process to improve its efficiency and to eventually obtain even larger single crystals.
Solar Salt (60 wt% NaNO3, 40 wt% KNO3), used in Concentrated Solar Power (CSP) Thermal Energy Storage (TES) technology, can decompose into various products at elevated temperatures, with oxide ions being one of the known corrosive byproducts. The study mimics Solar Salt aging by intentionally adding sodium peroxide (Na2O2) and sodium oxide (Na2O) at concentrations of 0.005–0.33 wt% to investigate their role in the corrosion of austenitic stainless steel at 600 °C in typical operating conditions. Salt chemistry (nitrite, nitrate, oxide ions, and metal cations) was analyzed every 24 h, and steel corrosion after 168 h was assessed by weight change, corrosion rate, phase analysis, and cross-sectional morphology. Results reveal that at or above 0.135 wt% added Na2O2/Na2O leads to a quasi-steady-state equilibrium of oxide ions in the salt. Interestingly, at these concentrations, the presence of steel further decreases oxide ion concentration. Furthermore, above 0.135 wt%, the corrosion rate increases significantly, along with increased spallation, porosity and disintegration of the corrosion layer, forming a non-protective layer. This study highlights the critical role of oxide ions in the corrosion process.
Sportplätze aus Kunststoffrasen haben sich im Breitensport etabliert, weshalb ihre Anzahl jährlich zunimmt. Dabei werden Umwelt- und Gesundheitsrisiken, insbesondere durch Mikroplastik-Austräge, kontrovers diskutiert. Um die ungenügende Datenlage zur Menge des Austrages an Mikroplastik zu verbessern, haben sich zwei individuelle Studien mit dieser Forschungsfrage mit Fokus auf den Boden-Grundwasser-Pfad befasst, deren Ergebnisse hier erstmalig gemeinsam vorgestellt werden. Die erste Studie simulierte unter Laborbedingungen Mikroplastik-Emissionen von drei Kunststoffrasen-Szenarien in unterschiedlichen Alterungszuständen und analysierte thermoanalytisch. Die zweite Studie untersuchte Grundwasser-Proben von zwei Realsportplätzen, die 1 m unter dem Grundwasserspiegel entnommen und spektroskopisch untersucht wurden. Dies ermöglicht erstmalig einen Vergleich von Mikroplastik-Austrägen über das Sickerwasser in verschiedenen Bodentiefen. Die Labor-Ergebnisse ergaben je nach Alterungszustand des Kunststoffrasenplatzes Mikroplastik-Emissionen zwischen < 0,1 μg/L und 26,8 μg/L in 30 cm Bodentiefe. Wohingegen in den Grundwasser-Proben der Realsportplätze ab 4 m Bodentiefe keine Kunststoffrasen-Partikel detektiert wurden. Dies deutet darauf hin, dass vermehrt Mikroplastik durch Alterung aus Kunststoffrasen entsteht und im Sickerwasser ausgetragen wird, aber der Boden Mikroplastik- Partikel ≥ 5 μm durch Filtrationseffekte zurückhält, sodass diese im Grundwasser nicht nachweisbar waren.
More than 400 iron hydrogen storage containers (also called bottles or cylinders exploded on the air strip Berlin-Tempelhof on May 25, 1894, leaving immense destruction. The Royal Prussian Materials Testing Institute was requested to investigate the material properties and to furnish an expertise, how an increased safety of such cylinders might be achieved for the future under protection of the interests of the air ship service, as for instance by improvement of delivery specifications or respective material inspections.
The studies conducted personally by the director Prof. Adolf Martens and his deputy Prof. M. Rudeloff represent one of the first comprehensive failure case investigations in history and initiated BAMs long tradition in failure analysis. Martens and his colleague elaborated quite detailed specimen plans and investigated original failure parts with a special emphasis on conspicuous fracture appearance, but also made comparison experiments with hardened as well as annealed samples. Experienced investigators might identify some first routines how to conduct failure analyses and the importance of Adolf Martens as a pioneer in this field becomes evident.
Martens publications about the original expertise Martens, 1896 [1] and [2] include detailed descriptions about the experimental procedures and specimen preparation. Also, quite modern materials testing technologies and machines have been utilized, as for instance light microscopy as well as the tensile testing machines developed by Werder and Pohlmeyer. As special features developed by Martens, precision strain measurements have been applied during respective tensile tests and the so-called micro-photographic apparatus has been adopted to produce photos of the investigated microstructures. Additionally, the publications contain at that time very valuable advices regarding appropriate materials selection for gas storage cylinders.
The present contribution provides a nearly complete and as exact as possible translation of the original report Martens, 1896 [1] written in Old German language. Only little changes have been made in the text for a better understanding.
The copper life cycle comprises numerous stages from the alloy production to the manufacturing and usage of engineered parts until recycling. At each step, valuable data are generated and stored; some are transferred to the subsequent stations. A thorough understanding of the materials’ behavior during manufacturing processes or throughout their product lifetime is highly dependent on a reliable data transfer. If, for example, a failure occurs during the service life, information about the manufacturing route can be of decisive importance for detecting the root cause of the failure. Additionally, the life cycle assessment hinges on the availability of data. Recording and storing interoperable structured data is, therefore, a thriving research field with huge implications for the economic strength of the manufacturing industry. In the KupferDigital project, it is demonstrated how an ontology‐based data space can be utilized not only as an innovative method for storing and providing interoperable life cycle data but also as a means to enable automated data analysis and evaluation, leading to new insights and the creation of new knowledge using semantic data and technologies. This work illustrates how data recorded at different research facilities can be integrated into one single data space, allowing queries across heterogeneous sources.
Concentrated solar power (CSP) systems commonly use solar salt as a high temperature heat transfer and storage medium. This study examines the effect of oxygen (O2) and nitrogen oxide (NO) gas concentrations on solar salt thermal stability and 310N stainless steel corrosion at 600°C up to 1224 h. The impact of the gas atmosphere (5–80 vol% O2 , 400–600 ppm NO) on salt chemistry, including nitrate, nitrite, oxide, and chromate ions, was analyzed, and corrosion behavior was evaluated through weight change, corrosion rate, and microstructural analysis. The results show that introducing NO gas concentrations ≥ 400 ppm with at least 5 vol% O2 stabilizes salt decomposition by controlling nitrite and oxide ion formation and promotes the development of a protective corrosion layer on the steel surface. Once this protective layer is formed, variations in oxygen concentration (5–80 vol%) in the presence of ≥ 400 ppm NO gas have a minimal long‐term effect on the corrosion behavior of stainless steel in solar salt. These findings underscore the importance of maintaining minimum O2 and NO levels to optimize salt chemistry that effectively mitigates steel corrosion in solar salt systems.
