Tribological behavior and wear mechanisms of Ti-C : H/TiC/TiCN/TiN/Ti coatings when sliding against steel, bronze and aluminum alloy rods

Ti-x%-C : H coatings of differing thicknesses and with various titanium con centrations were deposited on tungsten carbide disks by unbalanced magnetro n sputtering. The mechanical properties, microstructure, and adhesion stren gth of these coating were measured. The tribology properties of the coating s against AISI 1045 steel, AA7075, AA6061 aluminum alloy, and bronze rods w ere tested by an oscillation sliding test machine with a line-contact wear mode under dry conditions. The microhardness of Ti-x%-C : H coatings increa sed with an increasing Ti concentration. The optimum coatings are composed of an intermediate layer of TiC/TiCN/TiN/Ti and a top layer of Ti-x%-C : H with x less than or equal to 20%. These coatings have an excellent wear res istance and a low friction coefficient when paired with a carbon steel or c opper alloy. These pairs are marked by the mildly wear of the counterbodies of AISI 1045 steel and bronze. The coatings are less suitable for oscillat ion with the aluminum alloy under dry conditions due to severe adhesion dam age. (C) 2001 Kluwer Academic Publishers.