RESULTS ON THE THERMAL-STABILITY OF CATHODIC ARC-DEPOSITED (CR,B)N COATINGS

Chromium-Boron targets with 2, 10 and 20 at.% boron are applied in a c athodic are discharge with nitrogen as the working gas for the deposit ion of (Cr,B)N coatings on cemented carbide inserts. The discharge beh aviour of the target material is characterized. The chemical compositi on of the coatings is semiquantitatively analysed by glow discharge op tical spectroscopy. The thermal stability of the coatings is investiga ted by load-indentation measurements prior to and after tempering of t he samples at 700 degrees C under vacuum as well as under atmospheric conditions. TiN and CrxN coatings treated in the same cycles served as reference materials. Tempering under vacuum conditions proves a nearl y identical stability of the (Cr,B)N and the reference material coatin gs. After tempering under atmospheric conditions only, the (Cr,B)N coa tings show a nearly identical response to the penetration of the inden ter.