Mechanical, Thermal, and Tribological Properties of Amorphous Carbon Films

Abstract

In this paper, the correlation among the hardness, determined by the nanoindentation method, the thermal conductivity, by the 3ω method and friction coefficient, by the ball on disk (BOD) method; of tetrahedral amorphous carbon (ta-C) films deposited on Si substrates and WC/Co substrates by the filtered cathodic vacuum arc (FCVA) deposition method has been investigated. The films were also characterized by Raman spectroscopy and Rutherford backscattering/elastic recoil detection analysis (RBS/ERDA). The experimental results were discussed in terms of the microstructure of ta-C films depending on the kind of substrate. It was revealed that the hardness and the thermal conductivity of ta-C films on WC/Co substrates were higher than those on Si substrates and they increased with density. The increase in density was correlated with the decrease in ID/IG corresponding to the graphite cluster size La of the films. The density of a ta-C film on the wear track increased after BOD tests because of the mechanical stress during sliding.