IMPROVEMENT OF ADHESION CHARACTERISTICS BETWEEN COATING AND SUBSTRATE OF RESTORATION INSTRUMENTS BY USING INTERMEDIATE GRADIENT LAYER
This article describes the designing wear-proof tools of high-speed steel with superhard coatings of nc-TiN/a-Si 3N 4. A special attention is put to achieving high adhesion between the coating and the substrate by depositing an intermediate gradient layer which gradually changes its chemical composition from Cr to TiSiN. Within the work two experiments were conducted: the first one with use of the intermediate layer, and the second one without it. The specimen characteristics were obtained by scratching test using Rockwell indicator. The graphics part of the article presents: PVD apparatus chamber (magnetrons scheme and real view), surface morphology of the specimen polished cross-section, cross-sectional morphology of the substrate of high-speed steel, scratch test results as well as the graph of friction coefficient f and acoustic emission AE. The proper adhesion rate was the result of the experiments.