Growth of Large Diamond Crystals by Reduction of Magnesium Carbonate with Metallic Sodium

摘要

Diamond is a material with uniquely attractive physical, thermal, and optical properties, and is used in applications ranging from abrasives, tool coating, bearing surface, micro-electronics, and optics to corrosion protection. The diamond is grown commercially by using high-pressure and high-temperature, chemical vapor deposition for thin films and shock-wave processes. Alternative routes to diamond preparation include the reduction of CCl_4 by metallic sodium, and hydrothermal process with carbon, water, and metal near 800 ℃ and at 1.4 Kbar pressure. Recently, the synthesis of diamond-structure carbon from silicon carbide in chlorine-containing gases at temperatures not exceeding 1000 ℃ was also achieved. Herein we report the synthesis of high-purity cubic diamond particles by the reduction of magnesium carbonate with metallic sodium at a temperature as low as 500 ℃.