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

The properties of cold-gas sprayed coatings are usually related to spraying parameters such as gas temperature or gas pressure, which determine the impact velocity and temperature of the particle. The temperature of the substrate is not considered in most cases, but plays a major role in the deposition process. Substrate temperature significantly influences deposition efficiency, bond strength and coating properties. This is well known for thermal spray processes, and is currently under investigation for cold spraying as well, as substrate temperatures can rise up to several hundred degree Celsius.

In this presentation, the substrate temperature during spraying is controlled via an induction heating system at the backside of the sample and determined by a thermocouple as well as an infrared camera. The focus of this project is to deposit metallic coatings onto ceramic substrates. An increased substrate temperature enhances bonding and influences mechanical stresses as well as mechanical and electrical properties of the cold-gas sprayed coatings. This is investigated for copper and aluminium single-impacts and coatings on bulk ceramics and on thermally sprayed ceramic layers.