Properties of carbon films with a dose of titanium or zirconium prepared by magnetron sputtering

Carbon films containing titanium or zirconium on a stainless steel substrate were prepared using magnetron-sputtering sources with a target of carbon, titanium or zirconium. These prepared films were analyzed by X-ray photoelectron spectroscopy to determine the chemical state and the atomic composition, and by Raman spectroscopy and X-ray diffraction to define the film microstructure. The electrical resistivity measurement was carried out by the four-point d.c. method. The tribological property was measured by a tribo-tester of a pin-on-disk type. ical resistivity of the TixC1−x films decreased from an insulator as diamond-like carbon to 1.7×10−5 Ωm as titanium with increase of the value x in TixC1−x. Also the resistivity of ZryC1−x films showed the same behavior as the TixC1−x films. While the friction coefficient of the films increased with an increasing dose of titanium or zirconium, a low friction coefficient was obtained both of in the region of x or y=0.4–0.5. The optimum composition x or y to obtain both of the low electrical resistivity and low friction coefficient was investigated as follows. In the case of TixC1−x films, the optimum x was 0.2 in a high vacuum and 0.5 in an air atmosphere, while the composition y in ZryC1−x films was 0.6 in an air atmosphere and 0.4 in a vacuum, respectively.