Enhanced adhesion of diamond thin films on WC/Co substrates

A novel method for improving the adhesion of diamond films on cemented carbide tool inserts has been investigated. This method is based on the formation of a compositionally graded interface by developing a microrough surface structure using a pulsed laser process. The surface morphology and roughness were investigated with laser conditions. After the surface modification with the laser, etching treatment was applied to remove a cobalt binder and a modified tungsten carbide layer on the surface. Then the deposition of diamond film was carried out using a hot filament chemical vapor deposition (HFCVD) process. The surface roughness of the substrate was controlled by varying the number of pulses and the incident energy. At higher energy densities the formation of WC_1-x (X = 0-0.3) phase was observed, which further transformed to the W₂C phase with further increase in number of irradiated pulse.