Synthesis of industrial diamonds using FeNi alloy powder as catalyst

Synthesis of diamond single crystals in Fe₈₀Ni₂₀-C system was carried out in a cubic anvil high-pressure and high-temperature apparatus. This paper reports that the surface morphology and inclusion distribution of the grown diamonds had been observed. It finds that the inclusions in cubic and octahedral diamonds radiated along certain crystal orientation, while the inclusion distribution in cubo-octahedral diamond seemed independent of crystal orientation. By using scanning electron microscope, the surface morphology of the three shapes of diamonds was observed. The results of Mossbauer spectrum indicated that there were iron-inclusions Fe₃C and Fe-Ni alloy in the diamonds. According to the Fe-C phase diagram, FeFe₃C should have formed during the quenching process. Nickel might have an inhibitory effect on the formation of Fe₃C.