Potential of Cold Gas Spraying in Power Electronic Applications

A successful combination of isolating substrates with conducting metal coatings produced by cold spraying could open new industrial application areas like the fabrication of power electronic components. For minimizing the number of industrial process steps, isolating ceramic layers should ideally be processed by thermal spray techniques. Thus, the present study investigates the impact behaviour and coating formation of ductile metallic feedstock powders onto brittle ceramic coatings. With respect to high electrical conductivity of the metallic lines and good electrical isolation of the ceramic interlayer, copper was cold gas sprayed on previously thermally sprayed Al₂O₃ coatings. Successful cold coating formation requests different strategies for the activation of the ceramic layer to increase adhesion and to avoid brittle failure. Both can be achieved by applying a bondcoat on the ceramic layer or by using heated substrates during the cold spray process.