Preparation, characterization and wear behaviour of PACVD cermets

Commercial cermets inserts were coated with TiN(x), TiC(x)N(y) and (Ti, Si)N(x) by plasma-assisted chemical vapour deposition using a pulsed d.c. glow discharge. The influence of the coating parameters on the deposition rate, layer composition, layer-substrate interface, structure and microhardness of the layers was investigated within the deposition temperatures of 773-973 K. With optimized process parameters, layers with a low oxygen and chlorine impurity, high microhardness and a good adhesive strength are obtained. Higher microhardness values compared with that of TiN(x) were observed for TiC(x)N(y) and (Ti, Si)N(x) layers depending on the layer composition. Usually, the TiN(x) and also the TiC(x)N(y) and (Ti, Si)N(x) layers with low carbon and silicon contents have a columnar structure with a (200) texture. The structure changes with rising carbon and silicon concentrations. The edge life of the insert tips is markedly increased for cast iron and steel machining.