Pre-/post-treatment and finishing - Pre-treatment: Thermal spray deposition of metallic and ceramic coating on aluminium and titanium alloys using the PROTAL process

摘要

Surface preparation prior to thermal spraying is a key step in ensuring a good adhesion of the coating onto the part to be coated. Usually, substrates are initially degreased and grit-blasted, mainly with corundum. These steps are necessary to clean the superficial contamination (machining oil, handling, ...) and to form a rough surface, which provides mechanical bonding between the substrate and the coating. It is well known that residues of grease and oxide layers prevent close contact between the impinging particles and the substrate. Also, the surface roughness significantly influences the adhesion of the thermal sprayed coatings. Partial or complete melting and subsequent solidification of the surface layers close to the substrate/coating interface may lead to the formation of strong bonds [1].