Manufacturing of micro-structured functional magnesium components by transplantation of thermal sprayed coatings using lost cores during pressure die casting

• Applicants: Professor Dr.-Ing. Dirk Biermann; Professor Dr.-Ing. Kai Möhwald
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing ; Coating and Surface Technology ; Metal-Cutting and Abrasive Manufacturing Engineering
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 281145974

Aim of this research project will be to further develop the coating transplantation process and combine it with alternative materials and new innovative tool concepts. In the course of the coating transplantation the coating process is integrated into a die casting process by inserting a thermal spray coated mold insert into a die casting mold.During the casting process the melt infiltrates the pore network of the coating, creating a form locked joint. The feasibility of this process has already been proven for aluminum die casting. As an alternative casting material magnesium, with its excellent suitability for lightweight construction, is now in focus of this research project. Determining the difference to the transplantation process using aluminum based alloys and meeting the resulting challenges, not in the least, offers the opportunity to expand the basic understanding of the coating transplantation process. In this context it is also necessary to examine the specific corrosion problems resulting from the compound, consisting of coating and casting material, created during the transplantation process.The working hypothesis is, that suitable material choice and multi-layered coatings created by thermal spraying allow the coating structure to be adjust above and below the infiltration area as well as at the coating edges in such a way, that the increased corrosion resulting from the electrochemical potential of magnesium can be limited to a technically usable minimum.The usage of lost cores, especially salt cores, also shows great potential for the transplantation process. These would make it possible to produce components with a coated complex internal geometry. To this end, several challenges must be met. In addition to the difficulty of coating salt cores, several technical difficulties concerning production must be overcome and handling concepts be developed. The aim of the corresponding operating point will be to develop suitable processes for pretreating the surface of the salt cores for coating and to adapt the coating process accordingly, as well as to determine processing parameters which allow for the creation of complex geometries in salt. Based on the processing parameters the developed salt core geometries are provided by functional surface structures to enhance the characteristics of the manufactured workpiece.

• DFG Programme: Research Grants