Abstract
Scratch tests were carried out on TiC and TiN PVD-coating. Occurrence of AE signal and the change of frictional force during scratch test show local delamination of coating at the critical load, L_c, in agreement with the observation of scratch track on the specimen surface. The critical load, L_c, was obtained as 25 and 70 N for TiC and TiN coatings, respectively. In order to study damage process of coating during scratch test, cross section of scratch track were observed. Cracks perpendicular to the interface were observed in the coating layer on both of TiC and TiN coatings. Local delamination occurred at the edge of scratch track at L_c.
