ATTEMPTED HYDROTHERMAL SYNTHESIS OF DIAMOND BY HYDROLYSIS OF BETA-SICPOWDER

Hydrolysis of beta-SiC powder in the ''hydrothermal'' pressure-tempera ture regime (1.4 kbar at 800 degrees C) leads to a sharp Raman band at 1330 cm(-1). This suggests evidence for growth of diamonds under hydr othermal conditions. However, X-ray diffraction studies and scanning e lectron microscopy analysis do not provide the usual evidence for diam onds. Instead, they reveal euhedral monodisperse quartz crystals and a second acicular phase. It is possible that any diamond crystals are v ery small, with sizes of the order of few nanometers. However, transmi ssion electron microscopy analysis reveals that the whiskers are a sil icon oxycarbide with an approximate composition of SiO1.6C0.2 and have a width up to 100 nm and lattice imaging revealed 9.0 Angstrom spacin gs.