Relation of friction and wear to processing parameters of polycrystalline diamond films grown on silicon and silicon and silica substrates by the hot filament method

Abstract Polycrystalline diamond films were deposited on silicon and silica substrates in a hot filament chemical vapor deposition reactor using venous pretreatment times and methane gas concentrations. Friction and wear tests were performed with a pin-on-disc tribometer under 100 and 200 gf loads without lubrication in the ambient environment. Tests show that friction coefficients decrease with both increasing load and number of traces, which was attributed to the formation of graphite during wear. Wear tests indicate graphitization to be the primary wear mechanism, with occasional wear pits caused by grain pull-out. The formation of wear pits is believed to be related to the presence of amorphous carbon in a very small fraction of the grain boundaries.