TRIBOLOGICAL AND STRUCTURAL CHARACTERIZATION OF A PHYSICAL VAPOR-DEPOSITED TIC/TI(C,N)/TIN MULTILAYER

A physical vapour deposited TiC/Ti(C,N)/TiN multilayer was investigated and compared with a PVD TiN monolayer coating in a ball-on-disc test. Wear and friction against a corundum ball were measured as a function of time and sliding velocity. In these experiments, the coefficient of friction remained constant at 0.2 as long as the ball was sliding on TiC or intermediate Ti(C,N) layers. When the TiN layer was reached, the coefficient of friction became unstable and rose to an average value of 1-1.5, which is characteristic for a TiN/Al2O3 contact. Wear rates for the multilayer were found to be three to four times smaller as compared to the reference TiN. The multilayer morphology of the TiC/Ti(C,N)/TiN was revealed in a low-angle cross-section resulting from a prolonged ball-on-disc test. In that way, it was shown that the multilayer consisted of nine separate sublayers.