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Processes and active zones in oxygen-free atmospheres for the development of sustainable production techniques and manufacturing processes
All technically used inert gas and vacuum atmospheres still contain sufficient oxygen molecules, which lead to the rapid oxidation of metal surfaces. This limits the possibilities of many processing and joining processes. The Collaborative Research Center 1368 "Oxygen-free production" is based on the idea of adding a small amount of silane (a few ppm) to the inert gas argon. The silane reacts with the residual oxygen and water in the atmosphere and reduces the partial pressure of the oxygen to less than 10-23 bar. This partial pressure is equivalent to extremely high vacuums (XHV-adequate atmosphere). The CRC is concerned with the development and research of specific production processes for forming, shaping, joining, cutting and coating in an oxygen-free environment.
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Sub-project S01 "Central analytics"
Project leader: Prof. Dr. rer. nat. Wolfgang Maus-Friedrichs, Dr. rer. nat. René Gustus
Funding period: 01/2020 - 12/2027
Funding body: DFG
Researchers: M. Sc. Maik Szafarska (01/2020 - 06/2024), M.Sc. Sascha Jan Zimmermann (01/2024 - 12/2027)
The subproject S01 "Central Analytics" is mainly active as a service project in the Collaborative Research Center (CRC). The project provides a central infrastructure for surface and material analyses and serves as a central point of contact for corresponding investigations. The central analytics department is available to the sub-projects both in an advisory capacity and for direct experimental work. The analysis of surfaces and interfaces is an essential part of this CRC's research. A large number of manufacturing processes are significantly influenced by the nature of the surfaces and interfaces of the manufactured materials as well as the processes and mechanisms taking place at the surfaces and interfaces. First and foremost, the chemical composition and microstructural properties as well as chemical-physical processes such as oxidation, deoxidation and interdiffusion should be mentioned here. The relevant information depths range from a few nanometers to a few micrometers, meaning that different methods from the field of surface and material analysis must be used depending on the issue at hand. For surface and material analysis investigations, sub-project S01 can draw on the wide range of analysis techniques and equipment available at the Clausthal Center for Materials Technology (CZM). The spectrum ranges from analysis of the element composition at different depths of the surface to the investigation of the chemical bonds present on the surfaces and microstructure analysis. Central Analytics is responsible for planning, carrying out and evaluating the measurements, providing the results obtained in an appropriate manner to the commissioning sub-projects and thus contributing to the knowledge gained. Furthermore, the S01 sub-project supports the sub-projects in the preparation and interpretation of measurement results in the course of publications. If required, the Central Analytical Department also organizes XHV-adequate sample transport to the analytical department. The sample transfer system developed in the first funding period is used for this purpose. With this system, samples can be transported oxygen- and contamination-free from the process chambers of the sub-projects to the analysis devices of Central Analytics. This procedure will primarily be used for electron spectroscopic analysis methods such as X-ray photoelectron spectroscopy (XPS) and auger electron spectroscopy (AES). These methods are characterized by an extremely high surface sensitivity (information depth < 10 nm) and are used as standard under ultra-high vacuum conditions of 10-9 - 10-11 mbar (oxygen partial pressure typically < 10-12 mbar). This guarantees, among other things, that the samples cannot oxidize or react during the investigations, thus ensuring an unadulterated view of the sample surface. In the first funding period, the various analytical methods and techniques were successfully used in various contract analyses. Here, the Central Analysis Department was able to provide important support in the clarification of various surface and interface-relevant issues. In the second funding period, the contract analyses will be continued on the basis of the techniques developed and the experience gained. In addition to the planned contract analyses, sub-project S01 will also be involved in its own research work on the interaction of silane with water. In particular, investigations into the plasma-assisted reaction of silane with water will be carried out. The research work is based on findings from the first funding period. Using mass spectroscopy, it was possible to prove that, contrary to previous knowledge, no significant conversion takes place between silane and water at room temperature. A corresponding reaction conversion can only be observed at elevated temperatures (> 500 °C). The knowledge gained so far leads to the conclusion that the reaction between silane and water is kinetically strongly inhibited at room temperature. This finding is important, as water is also oxidation-promoting under certain conditions and can also influence the curing behavior of adhesives. As part of the planned research work, the extent to which the reactivity can be increased by means of dielectrically hindered plasmas (DBE) will be investigated.