Flame combustion enables the synthesis of diamonds via acetylene-oxygen gas flame combustion in ambient air. It has various advantages over other methods and there are desirable features in the industry. Recently, molybdenum has been used for the energy industry, aerospace industry, and electronic component manufacturing for applications in high temperature environments. To obtain high-quality diamond films with various synthesized diamond crystallite sizes and achieve good adhesion on a Mo substrate, diamond films were synthesized on a Mo substrate by the flame combustion method. However, the surface roughness of most of the diamond films synthesized by this method increased, and therefore, it was necessary to reduce this roughness. Considering the surface roughness accuracy of the workpiece in industry, and the performance of the manufacturing, 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 Mo 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 verified. The effect of amount of diamond paste with diamond seed particles on the diamond films synthesized by flame combustion was investigated. 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 analyzed.
TAKAHASHI et al. (2026) studied this question.