Tribological and mechanical properties of nanocrystalline TiAlN and TiSiN PVD coatings

Abstract

Abstract TiN, TiAlN and TiSiN coatings were deposited on the W6Mo5Cr4V2 steel substrate by hollow cathodic-assisted multi-arc ion plating technology. The tribological properties of these coatings are comparatively studied. The microstructure, element composition, nanomechanics and wear properties of the substrate and coating surface of high-speed steel were evaluated by XRD, SEM, EDS, TEM, XPS and nano-indentation test. The results show that the mechanical properties of ternary coating TiAlN and TiSiN are improved compared with high-speed steel and binary TiN coatings, with TiAlN hardness and elastic modulus of 44.8 GPa and 438.6 GPa, and TiSiN hardness and elastic modulus of 34.8 GPa and 333.2 GPa. TiAlN coating has the strongest ability to resist plastic deformation due to solid solution strengthening. TiSiN can improve the plasticity and toughness of hard coating after fine grain strengthening. There is a strong correlation between the amount of sample wear and H3/E*2 value, and the larger the H3/E*2 value, the higher the wear resistance of the sample. The surface friction coefficients of TiN, TiAlN and TiSiN were all small compared with high-speed steel, and the roughness at the wear tracks of high-speed steel increased, while the roughness at the wear tracks of the coating samples decreased.