Collaborative Research Center 1368 - Oxygen-free production
Processes and active zones in oxygen-free atmospheres for the development of future-proof production techniques and manufacturing processes.
In all technically used inert gas and vacuum atmospheres, there are still sufficient oxygen molecules that lead to rapid oxidation of metal surfaces. As a result, many processing and joining processes are limited in their possibilities. 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 lowers the partial pressure of oxygen to less than 10-23 bar. This partial pressure is equivalent to extremely high vacuums (XHV adequate atmosphere). The SFB is concerned with the development and research of concrete production engineering processes of forming, joining, separating and coating in an oxygen-free environment.
Subproject B04 "Adhesive-based assembly processes in XHV-adequate atmosphere with deoxidized and oxidized joining partners".
Project leader: Prof. Dr. rer. nat. Wolfgang Maus-Friedrichs, Prof. Dr. Ing. Annika Raatz
Funding period: 01/2020 - 12/2023
Funding body: DFG
Researchers: M. Sc. Philipp Moritz, Dr. rer. nat. Lienhard Wegewitz
The joining technology of adhesive bonding is playing an increasingly important role in assembly technology. In contrast to other joining processes, such as welding or soldering, adhesive bonding enables the construction of hybrid structures, i.e. the joining of dissimilar materials. In XHV-adequate atmospheres, metals can theoretically be bonded without intermediate oxide layers. This direct bonding offers potential for higher joint strength, new joining partner-adhesive combinations and thinner layer thicknesses. The aim of the subproject is to gain knowledge about technical properties of bonded joints produced in XHV-adequate atmospheres and with deoxidized joining partners, and to explore possibilities for new process design derived from this. The challenge in oxygen-free bonding is that, on the one hand, the adhesion mechanisms are affected by oxide layers, and on the other hand, the setting reaction of special adhesives is slowed down or favored by oxygen or water. The absence of oxygen and moisture in an XHV-adequate environment thus has a fundamental effect on the properties of an adhesive bond and the bonding process.
Subproject C01 "Elucidation of mechanisms and processes for the deoxidation of material surfaces and their implementation on a laboratory and pilot plant scale".
Project leader: Prof. Dr. rer. nat. Wolfgang Maus-Friedrichs, Dr. rer. nat. Sebastian Dahle
Funding period: 01/2020 - 12/2023
Funding body: DFG
Researcher: M. Sc. Viktor Udachin
Deoxidation of the surfaces of semi-finished products is an essential part of oxygen-free manufacturing. Furthermore, the elucidation of the mechanisms mediating deoxidation is an important basis in project areas A and B and in the work with semi-finished products containing oxide. The project will therefore investigate the mechanisms that can be used to deoxidize semi-finished products. Both the thermal and the plasma-chemical reduction of oxides of the construction materials iron, copper, aluminum and titanium, which are essential for the SFB, are addressed. Starting from basic investigations of the mechanisms, the reaction kinetics and the processes involved, a description of the thermal and the plasma chemical deoxidation will be formulated. In a further step, this knowledge will be transferred to the pilot plant scale, validated there and the description suitably extended. In this way, it will be possible to use the results in the other subprojects, especially in project areas A and B. In addition, questions will be jointly addressed there. In addition, questions there will be jointly addressed by simulating the observations of the other subprojects in model experiments. Only in the close cooperation within the SFB can further effects from the observations be elucidated and fundamentally described.
Sub-project C02 "Powder deoxidation
Project leader: Prof. Dr. rer. nat. Alfred Weber
Funding period: 01/2020 - 12/2023
Funding body: DFG
Metallic powders are used in numerous manufacturing processes (e.g. joining processes, additive manufacturing, coating) as additive and starting materials whose oxygen-free processing, as planned in the present SFB, requires prior deoxidation. In this project, gas-borne particles are to be freed from their oxide layers by plasma-induced chemical processes in reducing gases (hydrogen and silane in inert gas). In order to realize a well scalable process, the deoxidation shall be performed in a fluidized bed. In contrast to entrained flow reactors, the fluidized bed allows higher concentrations and residence times, while maintaining controlled conditions. Here, the deoxidation is performed in a circulating fluidized bed to repeatedly carry out the particles to be deoxidized at and or through the reactive plasma zones. After successful deoxidation, the particles are discharged from the fluidized bed via a cyclone separator and prepared for shipping or fed directly into an appropriate downstream processing step.
Subproject S01 "Central Analytics
Project leader: Prof. Dr. rer. nat. Wolfgang Maus-Friedrichs, Dr. rer. nat. René Gustus
Funding period: 01/2020 - 12/2023
Funding body: DFG
Researcher: M. Sc. Maik Szafarska
The subproject Central Analytics serves the uniform analysis and description of the surfaces and interfaces of the different subprojects in the SFB. The goal of the subproject is to establish and provide a central analytical infrastructure with the task to support the other subprojects of the SFB1368 in the elucidation of project-relevant surface and interface processes. The scientific core interest lies in particular in the elucidation of the fundamental mechanisms of the interaction of the joining partners, the processes during mechanical treatments under oxygen-free conditions as well as the investigation of the diffusion of metals into other metals during oxide-free contact. The establishment of a central infrastructure for the analysis of surfaces and interfaces is intended, in particular, to ensure the reproducibility and comparability of measurements necessary for the discussion of results and the formation of models. The Central Analytics subproject is responsible for planning, performing and evaluating the measurements and also organizes sample transport between the subprojects. In all process steps, from planning to documentation of results, Central Analytics is in close contact with the commissioning subprojects. In order to ensure the oxygen-free transport between the XHV-adequate laboratory chambers and the respective measuring equipment of the Central Analytics, which is urgently required for the cooperating subprojects, the establishment of a suitable sample transport system is planned. The sample transport is divided into two phases. In phase 1, the samples to be analyzed are transported to the central analysis facility via suitable transport containers in an XHV-adequate atmosphere and transferred to a transfer chamber on site. In phase 2, the samples are then transferred via special transfer systems to the respective measuring apparatus. Before the start of regular measurement operation, a detailed validation of the planned sample transport is carried out. For this purpose, well-defined oxide-free control samples are prepared, which pass through each phase of the sample transport. As soon as it is ensured that no oxygen contamination occurs during sample transport, the sample transport system is used in regular operation.