The role of grit blasting in the production of high-adhesion plasma sprayed alumina coatings

Abstract

This paper describes the adhesion mechanism of sprayed alumina particles on to grit-blasted surfaces. Two types of impacted particles are identified, these being disc and splash types of splats. The impact of the splats on various surfaces is identified which indicates why grit-blasted surfaces are considered the best. A series of surfaces has been prepared in which the alumina is built up to full coverage. The proportion of splats in the valleys, on flats and on peaks is identified for high-and low-adhesion samples. This is related to the definition of grit-blasted topography for manufacturing quality assurance.