Effect of Oxygen on Diamond Crystallization in Metal–Carbon Systems
Yuri N. Palyanov, Yuri M. Borzdov, Igor N. Kupriyanov, Yuliya V. Bataleva, Denis V. Nechaev
Abstract
≥ 5 wt %, diamond crystallizes jointly with wustite (FeO) and metastable graphite. The oxygen solubility in the iron-nickel melt is estimated at about 2 wt %. With increasing oxygen content in the system, the range of nitrogen concentrations in diamonds crystallized in one experiment significantly broadens with the maximum nitrogen concentrations being increased from 200-250 ppm in the experiment without O additives to 1100-1200 ppm in the experiment with 10 wt % O added. The established joint growth of diamond and wustite suggests possible crystallization of natural diamonds in the Fe-Ni-O-C system over a wide range of oxygen concentrations up to 10 wt %.