On catalytic action of nickel, copper and nickel-copper alloy in graphite-diamond phase transformation

Synthetic diamonds were grown by subjecting spectroscopic grade graphite to static high pressures and temperatures in the presence of copper, nickel a nd their alloy namely monel as catalyst solvents. Diamond formation in the presence of conventional catalysts (nickel and monel) takes place immediate ly after their melting temperatures. However, the catalytic action of coppe r was found to be altogether different from the well known iron group metal s and alloys (nickel and monel) in that it is found to be inert with graphi te near its melting temperature, however at much higher temperature it beco mes an active catalyst and leads to diamond formation. The graphite-diamond phase transformation in presence of these catalysts is discussed based on experimental evidences.