Synthesis of nanocrystalline diamond films on smooth WC-Co cemented carbide substrates

Abstract

Nanocrystalline Diamond Films (NDFs) are deposited on WC-Co cemented carbide substrates by the bias-enhanced hot filament Chemical Vapour Deposition (CVD). A new pretreatment method is performed to diffuse boron into WC-Co substrate without surface roughening of smooth substrates. The new CVD processes are used to enhance the secondary nucleation, reduce the grain size of nandiamond and promote the growth of NDFs by appropriately increasing acetone concentration, lowering the reactive gases pressure and adding Ar gas in the reactive gases. Research results show that the boronization pretreatment can result in the formation of the stable cobalt boride compounds on the substrate surface, thus effectively ensure the adhesion of smooth diamond films. NDFs consist of nanocrystalline diamond with grain sizes range from 20 to 60 nm. The surface roughness of NDFs is measured at Ra < 50 nm. The diamond-coated drawing dies with these NDFs show obvious effect in the practical application.