Tribological Properties of MCD Films Synthesized Using Different Carbon Sources When Sliding Against Stainless Steel

Abstract

The carbon source adopted in deposition processes of bias-enhanced hot filament chemical vapor deposition diamond films has significant influences on basic, mechanical and tribological properties of as-deposited films. In the present study, pristine microcrystalline diamond (MCD) films are deposited on both WC-6 wt% Co flat and drawing die substrates, using the same deposition parameters and four typical carbon sources, including the methane, acetone, methanol and the ethanol. As-obtained MCD-coated and WC–Co flat specimens are all applied for standard tribotests, systematically analyzing the typical stages of their friction coefficient curves as functions of the sliding time, differences between tribological properties of MCD films deposited using different carbon sources, as well as effects of the normal load and the sliding velocity adopted in the test, which are closely related to their surface features, composition transformations and mechanical properties. Moreover, MCD-coated and WC–Co drawing die specimens are applied for special-designed wear tests in order to compare their wear rates and removal times, further clarifying the material removal mechanisms, as well as similarities and differences compared with actual applications of diamond-coated drawing dies.