Non-metallic catalysts for diamond synthesis under high pressure and high temperature

Recent results on conversion from graphite to diamond by aid of non-metalli c catalysts are reviewed. The current status of experimental advances is pr esented and typical examples from relevant literature ore provided for unde rstanding the mechanism of the graphite-diamond conversion by aid of these non-metallic catalysts. Furthermore, a tendency of graphite-diamond transfo rmation assisted by carbonates, sulfates or phosphorus under high pressure and high temperature has been investigated by calculating the activation en ergy and transformation probability of the carbon atoms over a potential ba rrier. It was found that the activation energy is highly sensitive to the c atalyst chosen. The probability sequence of graphite-diamond transformation with these catalysts was put forward.