Influence of Diamond Seed Attachment Processing on Diamond Films Synthesized on Tungsten Carbide Substrate by Flame Combustion

The flame combustion method enables the synthesis of diamonds via acetylene-oxygen gas flame combustion in ambient air. Tungsten carbide (WC) has recently been utilized as a cutting tool in the machining industry and in dental machining applications. To obtain high-quality diamond films and achieve good adhesion on a WC substrate, diamond films are synthesized on a WC substrate by the flame combustion method. However, the surface roughness of most of the diamond films synthesized by this method increased, and it was necessary to reduce this roughness. Considering the roughness accuracy of the workpiece surface during cutting, and the performance of the cutting tool, a smaller surface roughness of the diamond films synthesized is desirable. In this study, to reduce surface roughness, the amount of diamond paste with diamond seed particles as generation nuclei was carefully varied for diamond seed attachment processing of diamond films. When diamond films were synthesized on the WC substrate surface via the flame combustion, the amount of diamond paste with diamond seed particles affected the surface morphology and surface roughness of the synthesized diamond films. Furthermore, to investigate the reason for this result, generation of nuclei on the substrate in the initial stages of synthesis and diamond seed particles on the substrate surface after the seeding treatment were observed by scanning electron microscopy. The effect of diamond seed attachment processing on the diamond films synthesized by flame combustion was studied. The relationship between the surface roughness, number of diamond generation nuclei on the substrate in the initial stages of synthesis, number of diamond particles on the substrate after the diamond seeding process, and amount of diamond paste were confirmed.