CHARACTERIZATION AND WEAR BEHAVIOR OF SIC COATINGS PREPARED BY ION-BEAM-ASSISTED DEPOSITION

We have studied the influence of temperature and ion bombardment durin g deposition on the structure and the tribological properties of Si co atings. A SIC target was sputtered with 1.2 keV Ar+ ions delivered by a Kaufman-type source and the growing films were continuously bombarde d with 160 keV Ar+ ions. The microstructural state of the films was in vestigated by various techniques: transmission electron microscopy; gl ancing X-ray diffraction; and Fourier transform IR spectroscopy. It wa s found that SiC films prepared at room temperature without ion bombar dment are amorphous whereas those deposited by dynamic ion mixing (DIM ) exhibit the beginnings of a crystallization process into the beta-Si C phase. When the deposition temperature was increased up to 750 degre es C, the films prepared by DIM were more crystallized with a greater number of larger nanocrystalline grains of beta-SiC The wear resistanc e of TA6V (Ti 90 at.%-Al 6 at.%-V 4 at.%) substrates coated with SiC f ilms is always reduced. However, the films prepared by DIM exhibit a l ower wear rate as a result of increased adhesion. The crystallization of the films is discussed and analyzed as a consequence of collisional effects induced by the high-energy ion bombardment.