Molybdenum carbide MoCx thin films deposited by reactive magnetron sputtering

Molybdenum carbides possessing high hardness are studied in the context of their tribological properties. Thin films of MoCx were deposited on steel (4H13) and alumina substrates by reactive magnetron sputtering controlled by optical emission spectroscopy method. Structure and phase composition of deposits were studied by means of X-ray diffractometry and XPS. Results of microhardness and electrical conductivity are shown. Tests of dry friction in air of normal humidity were carried out in ball-on-disc configuration in the temperature range 20-400 oC. Tribological behaviour of studied coatings was discussed in terms of processes occurring at the surface of the coating during high temperature tests. The best results were found for nanocomposite coatings containing nanocrystalline molybdenum carbide embedded in the matrix of amorphous, hydrogenated carbon. (author)