Early stage of diamond formation on carbon/carbon composites

Diamond formation on two types of carbon composites was investigated using a plasma-enhanced chemical vapor deposition system. The effects of oxygen and the addition of copper into the carbon composites at the early stage of diamond formation were examined. Linear growth rates of diamond crystals under various deposition conditions were determined. It was found that the nucleation density of diamond was not affected by the addition of O2 in the region of 0–0.3%. However, the growth rate decreased with increasing oxygen content. Also, the presence of copper enhanced the growth rate. This effect could be, however, hindered due to the addition of oxygen.