Quantitative evaluation of residual grits under angled blasting

Grit blasting can contribute greatly to an improvement in adhesiveness of ceramic coatings, but the residual grits on the substrate surfaces degrade adhesion. Thus, grit blasting produces a good effect in one way and a bad effect in another. Specimens were roughened by angled grit blasting, and the residual grits were evaluated after air-blowing off the roughened surfaces. To evaluate quantitatively the residual grits on those substrates, the images of residual elements from EPMA are analyzed by computer, and their areal fraction is derived with respect to the blasting angle. It was concluded that grit residues occur mostly at a blasting angle of 90 degrees and decrease with decreasing angle. (C) 1999 Elsevier Science S.A. All rights reserved.