A Definition of the Topography of Grit-Blasted Surfaces for Plasma Sprayed Alumina Coatings

Abstract

This paper describes the topographical implications of grit blasted surfaces on plasma sprayed alumina. The transition of the grit blasted surface from raw material to correctly blasted is described in terms of surface heights, height distribution, spacings and texture. The influence of embedded grit is shown to be significant. The individual particles of alumina impacting the surface are classified into two types, these being disc splats and splash splats. Their deposition relationships with regard to surface topography and adhesion is explained with reference to the two types of splat.