Tribological Properties of CVD Diamond Films against Graphite

Abstract

In this investigation, micro crystalline diamond (MCD) and nanocrystalline diamond (NCD) films are deposited on cemented carbide (WC-Co) balls by hot filament chemical vapor deposition (HFCVD) technique. After deposition, MCD and NCD films are characterized by field emission scanning electron microscopy (FESEM) and Raman spectroscopy. Then frictional tests are carried out between CVD diamond coated balls and graphite. The results show that the MCD-graphite and NCD-graphite tribo-pairs exhibit comparable frictional coefficients, while the wear rate of graphite in MCD-graphite working pair is much higher than that of graphite in NCD-graphite working pair. Furthermore, the element oxygen is detected in the wear groove of graphite, suggesting the oxycarbide of working materials at the increased temperature due to the heat generated from the mechanical friction.