Fretting wear of thin diamond films deposited on steel substrates

The dominant wear mechanism of thin diamond films deposited onto steel substrates and the effect of film thickness on their lifetime under fretting conditions were studied by analyzing the running-in and the main period of the coatings wear life. Steel plate and steel ball specimens for the present study were both coated with diamond by chemical vapor deposition (CVD). The wear tracks resulting from the fretting tests were investigated by various surface analysis methods. The results showed that the dominant wear mechanism of the diamond coatings, when both surfaces are coated, is an abrasive form of fretting wear. Under these conditions, the lifetime of the diamond films increased with increasing film thickness. It was found that the wear rate during the main period is independent on the initial thickness of the diamond film and therefore its life depends on the residual thickness at the end of the running-in period.