Peculiarities of interaction in the Zn-C system under high pressures and temperatures

The wettability of graphite by a melt of zinc at 8.0 GPa in the temperature range 1900-3100 K has been investigated experimentally, and the temperatur e dependence of the wetting angle of graphite by the zinc melt determined. A polycrystalline diamond layer has been revealed at the interface in the z inc-graphite system in the diamond stability region. Metallographic and X-r ay studies of zinc-carbon alloys obtained under high pressure have been car ried out. The existence of the carbide ZnC2 was found, which participates i n two three-phase, non-variant equilibria in the system. It is determined t hat octahedral diamond crystals form in high-carbon alloys of zinc at the p ressure of 8.0 GPa between 2100 and 2500 K. (C) 2000 Elsevier Science S.A. All rights reserved.