Effect of substrate curvature on the properties of PVD coatings

The properties of TiN coatings on substrate surface areas in the vicinity o f edges with a small radius of curvature were investigated by means of a mo dified scratch test. The scratch track width was used as a parameter for ch aracterizing coating adhesion, microhardness and compactness. The results s howed a strong relationship of coating parameters to the edge radius and bi as voltage during coating deposition. Also it was confirmed that, for an ed ge radius of 5-10 mu m, there exists an area near the edge where internal s tresses could cause spontaneous failures of the coating-substrate integrity . (C) 1999 Elsevier Science S.A. All rights reserved.