STRUCTURE, COMPOSITION AND TRIBOLOGICAL PROPERTIES OF CARBON NITRIDE FILMS

Carbon nitride (CNx) films were synthesized using reactive magnetron s puttering of a high purity graphite target under argon/nitrogen atmosp here using various substrates held at the temperature below 453 K. Typ ically, the films were grown at the rate of 0.025 mu m x min(-1) to ob tain a total thickness of 2.0 mu m. The analyses of chemical compositi on made by Rutherford Backscattering Spectroscopy (RBS) and Energy Dis persive X-ray Analysis (EDAX) showed that the maximum amount of nitrog en introduced to the films is equal to 37 at.%. The Raman-spectra and Atomic Force Microscopy (AFM) analyses show that CNx films have an amo rphous structure and replicate the substrate topography, giving rise t o surface roughness equal to or better than the original substrate. Th e hardness measurements showed microhardness of the films up to 22 GPa . Good adhesion (L-c > 80 N) was obtained after applying a metallic in terlayer and a substrate bias voltage of -300 V d.c. The unlubricated ball-on-disc tribotesting of the CNx films showed that a friction coef ficient against bearing steel was equal to 0.45 and good wear resistan ce was achieved for the sample made with a substrate bias voltage of - 300 V d.c. The paper presents investigation results and a discussion r egarding the influence of argon/nitrogen atmosphere composition and su bstrate bias voltage on the properties of CNx films. (C) 1998 Elsevier Science S.A.