Abstract
The focus of this study is to deposit metallic coatings onto ceramic substrates for application in power electronics. One possibility to achieve the required surface activation is to heat the substrate during spraying. An increased substrate temperature significantly influences bond strength and coating properties. This is investigated for cold-gas sprayed copper and aluminum on thermally sprayed Al2O3 layers. The study examines the adhesion of single-impacting Cu particles as well as coating microstructures and mechanical and electrical coating properties. It is found that increasing the substrate temperature as well as increasing the surface roughness enhances the adhesion strength of single particles. Coatings sprayed on heated substrates adhere very well and show low compressive stresses. Their hardness is reduced significantly, while their electrical conductivity is optimized to values of over 90 % IACS (IACS: International annealed Copper standard, 100 % IACS equals 58 MS/m).
