Development of thermal spray coating solution for ceramic substrates

For modification of their surface properties, there exists an increasing need to apply thermal spray coating solutions also on ceramic substrates. Depending on the structure and the properties of these substrates, special concepts for substrate preparation have to be developed. In this contribution, several concepts for coating deposition on sintered Si3N4 and AIN ceramics are presented. The use of conventional sandblasting resulted in low roughening and induced damage at the near-surface region of the substrate. As alternative, laser ablation was used to modify the surface properties of ceramics for thermal spraying. By appropriate selection of laser ablation parameters and spray processes, APS and suspension-HVOF Al2O3 coatings with good bonding on the ceramic substrates were successfully produced.