THE ROLE OF GRIT BLASTING IN THE PRODUCTION OF HIGH-ADHESION PLASMA-SPRAYED ALUMINA COATINGS

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