Study of the stability of n-diamond

Powders of n-diamond can be synthesized by pyrogenation of carbon black and nanometre-sized iron catalyst at atmospheric pressure and at a temperature of l 100 deg C. The stability of n-diamond was investigated with x-ray diffraction, thermal gravimetric analysis and differential thermal analysis. The results indicated that n-diamond was a metastable phase: it can decompose at room temperature slowly. Thermal decomposition of n-diamond begins at 150DGC and is complete at 400 deg C, and the decomposition of n-diamond was an exothermic reaction.