Effect of Si3N4 substrate surface roughness on the wear resistance of diamond film prepared by HFCVD

Abstract

Diamond films were prepared by hot wire chemical vapour deposition on silicon nitride substrates with different surface roughness, and their properties were examined and analysed. The surface morphology of the crystallised silicon nitride substrates and the prepared diamond films were examined using field emission electron scanning microscopy and atomic force microscopy. The friction coefficient and wear rate of the diamond films were tested under dry friction conditions using a multi-functional friction and wear tester and a probe profiler. The effect of substrate roughness on the quality of the implant, the surface morphology of the diamond film, and the friction wear test results were combined to determine the effect of the surface roughness of the silicon nitride substrate on the wear resistance of the diamond film. The results show that the surface roughness of the substrate affects the uniformity and denseness of the implant, which in turn affects the growth of diamond particles on the surface of the substrate. The surface morphology of the substrate is also reflected on the surface of the diamond film. The substrates with surface roughness of 0.15 μm and 0.20 μm have good wear resistance, with the lowest wear rate of 1.75x10−7 mm3/mN and the lowest coefficient of friction of 0.078.

Keywords

• si3n4
• surface roughness
• hot filament chemical vapour deposition （hfcvd）
• diamond films
• wear resistance