Structure and tribological properties of carbon and carbon nitride films, obtained by the ARC method

Carbon and carbon nitrides (CNx) films were obtained by the cathodic are pl asma deposition method using a high-purity graphite target, nitrogen and ar gon as the working atmosphere and bearing steel as a substrate, held at 453 K. The films were analysed using energy-dispersive X-ray analysis and SEM, microindentation tests with FISHERSCOPE, adhesion tests with REVETEST(R) a nd tribology test with a ball-on-disc method. X-ray diffraction analysis re veal that the carbon and CN, films structure are mainly amorphous (a-C). Th is result was also confirmed by SEM pictures of fracture cross-section. Max imal microhardnesses of a-C and CNx films were 32 and 36 GPa, respectively. Good adhesion (L-c > 70 N) was obtained using a 0.2 mu m Zr interlayer. Th e maximum nitrogen concentration of the CNx films was about 23 at%. The coe fficient of dry friction against bearing steel is equal to 0.2 for a-C and 0.4 for CNx films. The paper presents investigation results and a discussio n of the influence of selected technological parameters on the properties o f a-C and CNx films. (C) 1999 Elsevier Science Ltd. All rights reserved.