Effect of Substrate Temperature on Cold-Gas-Sprayed Coatings on Ceramic Substrates

This study focuses on cold-gas-sprayed deposition of metallic coatings onto ceramic substrates for application in power electronics. In order to achieve the required surface activation for bonding, the substrate is heated during spraying. The effects of substrate temperature on bond strength and coating properties are investigated for cold-gas-sprayed coatings of copper and aluminum on Al₂O₃. It is found that the adhesion strengths of the cold-gas-sprayed coatings and that of the single-impacting particles increase with the increasing temperature and roughness of the substrate. Coatings sprayed on heated substrates show relatively low compressive stresses and low hardness, while their electrical conductivity reaches high values of over 90% IACS. Overall, a higher substrate temperature is found to improve the coating properties significantly.