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MORPHOLOGICAL FEATURES OF GRAPHITE MANIFESTATION IN EXPERIMENTS WITH SURFACE GRAPHITIZATION OF SYNTHETIC DIAMONDS

V. M. Sonin, I. A. Gryaznov, E. I. Zhimulev, A. I. Chepurov

Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, Russia

The results of studying the surface graphitization of diamonds by optical and scanning electron microscopy in various experimentally realized conditions are presented: at 2–4 GPa, 1450–1550 °C in carbonate medium and at 1000 °C and atmospheric pressure in a flowing medium of wet argon. It is determined that a dense optically opaque shell is formed on diamond crystals in a carbonate medium. As a result of an oxidation in wet argon, the surface graphite forms an unequal translucent film on diamond crystals. The represented conditions at high P-T parameters in a carbonate medium simulate the presence of diamonds in metamorphic complexes of ultrahigh pressures, and the wet argon medium simulates the presence of impact diamonds in astroblemes.

Keywords: diamond, surface graphitization, high temperatures and pressures.

DOI 10.20403/2078-0575-2024-4a-56-62

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