Planar fractal characteristics of blasted surfaces and its relation with adhesion strength of coatings

Adhesiveness of ceramic coatings is strongly dependent on the surface characteristics of blasted substrates. The roughened surfaces have two types of topographical characteristics, cross-section and planar. The roughened surface is generated by an angled grit-blasting process which can be expected to improve the adhesiveness of ceramic coatings. The topography of the roughened surfaces has fractal characteristics in their cross-section and has been more effectively related to the adhesive strength of ceramic coatings than the average surface roughness traditionally used. This paper presents that fractal characteristics are evaluated in the planar topography of the blasted surfaces and shows again that the planar fractal characteristics are closely related to adhesiveness of ceramic coatings. The planar fractal dimension is evaluated by SIA (Slit Island Analysis) which needs the height data of the roughened surface. These data are obtained by laser-microscope in confocal type.