TRIBOLOGICAL BEHAVIOR OF TIN, TICXNY AND TIC COATINGS PREPARED BY UNBALANCED MAGNETRON SPUTTERING TECHNIQUES

TiN, TiC and TiCxNy (0<x<1, 0<y<1) coatings were deposited onto AISI 420 substrates by unbalanced magnetron sputtering techniques at the substrate temperature of 350-degrees-C. The structures of all the coatings were examined by X-ray diffraction and Rutherford backscattering spectrometry. TiN and TiCxNy coatings exhibit a strong (111) or (200) preferred orientation. TiC coating exhibits a (220) preferred orientation. The hardness values for all the coatings increase with the carbon content varying between pure TiN and pure TiC coating. The different tribological behavior of TiN, TiC and TiCxNy coatings were investigated and compared. The amount of surface wear was evaluated by optical and scanning electron microscopy. The results of the wear tests show that friction coefficients are in the range 0.17-0.3 for all coatings. The wear lifetimes of the TiCxNy coatings with different carbon concentrations increase with the carbon content from 11 to 32 h. Relative soft TiN coatings exhibit a short wear lifetime, about 3.5 h. In general, the wear behaviors of TiCxNy coatings with high carbon content are superior to those of either TiN or TiC coating.