Materials Synthesized from Molten Diamond

Abstract

Liquid carbon was formed by the melting of diamond and the metastable melting of graphite in the diamond stable regions at 15 and 18 GPa. The diamond crystallized by cooling the molten carbon was investigated by visible and ultraviolet absorption spectra, cathodoluminescence (CL) and transmission electron microscopy (TEM). The diamond contains nitrogen and is classified as Type I. The color centers of blue band A, green band A, H3, 575 nm and N3 were found and a vacancy-type dislocation loop and a cavity with a cuboctahedral shape were observed in the diamond. The solidification behaviors of a diamond from the molten C-BN and C-aluminosilicate are also discussed.