WEAR AND FRICTION PROPERTIES OF NANOCOMPOSITE a-C:H/Ag THIN FILMS DEPOSITED BY A HYBRID PVD-PECVD PROCESS

Ag containing a-C:H nanocomposite films with various Ag content ranging from 0 to 8.3 at. % were deposited using a hybrid deposition process combining d.c. magnetron sputtering and PECVD. The influence of Ag content in the films on the structure, mechanical properties, wear and friction properties of the a-C:H films were studied using Raman, HRTEM, nanoindentation, residual stress measurement and ball-on-disc test. The introduction of Ag resulted in the formation of silver nanoparticles of 2-4 nm which increased the graphite-like (sp(2) bonding content) structure and promoted a decrease in the hardness and residual stress. Ball-on-disc tests were carried out in dry sliding conditions against a 440C stainless steel ball at a load of 5 N. Wear test results indicated that tribological behaviour of the a-C:H/Ag nanocomposite films was strongly dependent on the silver content in the films. The a-C:H/Ag films showed an increase in friction coefficients and wear rates with increment of Ag concentration.