Diamond coatings on surface-modified carbide tools using KrF pulsed laser

The surface of a cemented carbide was modified using a KrF pulsed laser process to achieve a microrough structure, leading to stronger adherence of diamond films to cemented carbide substrates. The surface morphology and roughness were investigated with laser conditions. After the surface modification with the laser and the etching of the modified surface, heat treatment was performed prior to deposition of diamond film in order to observe changes in surface morphology and adhesion. Diamond films were grown by chemical vapor deposition process. The results indicated that the heat treatment of the modified cemented carbide improved the adhesion of diamond films by the recrystallization of tungsten carbides into the fine and long grains. As laser energy for the modification of a cemented carbide increased, the surface roughness increased and tungsten carbide (WC) was transformed to WC_1-x(X = 0-0.3) and then to W₂C.