Evaluations of mechanical properties of DLC film by indentation method and the effect of substrate

This paper discussed the fracture mechanism of diamond like carbon (DLC) film subjected to contact loading. The DLC films with the thickness of about 12μm were deposited onto SUS304, SUS410 and WC-Co substrates by radio frequency (RF) plasma-based ion implantation method. Dual indenter method was applied to determine the stress-strain response of the films. Rockwell indentation tests with simultaneous monitoring of acoustic emission (AE) and corrosion potential fluctuation (CPF) techniques were also applied to the films to evaluate the static tensile strength. FEM analyses demonstrated the stress distribution under indentation testing and correlated the film fracture behavior with static strength of the films, which was assumed to be independent of the substrate materials based on the results of Raman spectra and indentation tests. Cyclic indentation tests were performed on the DLC film deposited onto WC-Co in order to evaluate the fatigue strength of the film. The cyclic fatigue was found to degrade the film strength compared to the static property.