MICROSTRUCTURE AND PROPERTIES OF ION PLATED Ti-B-N FILMS

Ti–B–N films, ∼3μm in thickness, containing 5–16 at.-%B have been deposited on W18Cr4V high speed steels and stainless steels using ion plating. The Vickers microhardness of the films was as high as 35–45 GN m^-2 (load 0·25 N) and the critical load during scratch tests 11–15 N. The film/diamond stylus sliding friction coefficient is 0·086–0·097 (load 8·8 N). X-ray and electron diffraction analyses have indicated that the film consists mainly of fcc TiN with dispersed simple orthorhombic TiB, cubic BN, and simple hexagonal Ti–B–N phases. SEM and TEM micrographs of longitudinal and cross-sections of the films show that the film has a very fine, dense fibrous nanocrystalline structure, with grain sizes ranging from several to tens of nanometres. The titanium, boron, and nitrogen contents are homogeneous within the film. A diffusion zone has been shown to exist at the film/substrate interface by ion probe microanalysis and EDAX examination.