Diamond Polycrystal Powder Formation Directly from Gas Phase in a Plasma Jet System

Diamond polycrystal powder has been produced directly from gas phase in an arc discharge plasma jet system. Acetylene diluted in argon was used as hydrocarbon source gas. The product was the mixture of diamond polycrystal powders and soot. The 3C cubic phase diamond which is dominant, and the mixture phases of cubic and 6H hexagonal diamond are identified in the produced diamond polycrystal powders by electron diffraction patterns.