The synthesis of diamond in thermal plasma processing under low pressure

In order to clarify the growth mechanism of diamond, we have studied experimentally on the influence of some key parameters (i. e. CH_4/H_2 ratio, the substrate temperature, the surface condition of the substrate etc.) to the synthesis of diamond by using the forced constricted type plasma jet generator. According to the present experimental results, it is confirmed that the arc discharge and the resultant plasma flow aren't affected by injecting H_2 and CH_4 gas, that diamond particles have been successfully synthesized on molybdenum substrate under pressure from atmospheric pressure to 100 Torr by selecting the experimental conditions, and that the most significant parameters on the synthesis of diamond are the CH_4/H_2 ratio and the substrate temperature.