Comparison of the mechanical performance of cutting tools coated by either a TiC _xN _1-x single-layer or a TiC/TiC _0.5N _0.5/TiN multilayer using the hollow cathode discharge ion plating method

TiC _xN _1-x single-layer (x=0-1.0) and TiC/TiC _0.5N _0.5/TiN multilayer coatings prepared using the hollow cathode discharge (HCD) ion plating method were investigated to improve the mechanical performance of high speed steel cutting tools. The carbon/nitrogen ratio of the TiC _xN _1-x coating was controlled by adjusting the composition of an additional acetylene/nitrogen mixture gas during the ion plating process. The mechanical performance characteristics of the coated cutting tools, such as the surface hardness, adhesion, wear and dynamic hardness, were studied. The cutting tools coated by the multilayer films showed higher wear resistance and longer use life than those coated by TiC _xN _1-x single-layer films. The higher dynamic hardness of the multilayer coatings was considered the primary contributor to the improvement of the mechanical properties.