Characterization of diamond-like carbon films by fine scale indentation measurements

Ultramicrohardness experiments have been performed on diamond-like carbon films prepared by plasma assisted PVD. Films were examined using a diamond indenter with the so-called Berkovitch geometry. Both the elastic and plastic properties of the films were characterised. Mechanical property measurements involved impressing an indenter into the film surface and producing continuous plots of load vs. depth during both loading and unloading (i.e. hysteresis curves). The method was used in this case to investigate whether the mechanical properties of DLC films produced over a TiN layer differed from those without the layer, since the former gave significantly better tribological properties. Evidence from the tests showed that the near-surface properties were similar demonstrating that the improved performance was due to the improved load support from the TiN layer.