Diamond Deposition on WC-Co Cemented Carbide by Means of Hot-Filament Method

The diamond deposition on WC-Co alloy substrate was studied using so-called hot-filament method, according to the depositing conditions previously published. To clarify the phenomena, model experiments using the substrate of coarse WC-10%Co alloy, the surfaces of which were treated in different ways, were mainly conducted. The substrate temperature from 1073 to 1223 K was needed for the diamond deposition. The number of diamond particles increased, when the substrate surface was scratched, and it further increased when the surface was etched to some extent to remove the binder after the scratching. As for the etched substrate, diamonds deposited after several minutes of reaction time at the edge of WC particles or at the edge of scratches on the particles. The incubation period for diamond deposition was clearly observed for the non-etched substrate. The carbon absorption of binder and the graphite formation on binder during reacting were confirmed. It was demonstrated that the adhesion between diamond and substrate for the etched substrate was sufficient enough, in good contrast to the case of non-etched substrate. The mechanism of adhesion mentioned above was described.