Effect of dispersion strengthening of a catalyst on the properties of polycrystalline carbonado diamonds

Abstract

Polycrystalline carbonado diamonds are synthesized from a carbon material in the presence of a nickel alloy catalyst. A polycrystal is a composite material that consists of a diamond phase and a binder (up to 20%) whose composition is close to the catalyst. The properties of the binder significantly affect the properties of the composite material as a whole. The strengthening properties of nickel alloys can be improved by doping them with disperse particles. In this study, we determined the conditions for forming the dispersion-strengthened binder in a polycrystalline diamond. Carbonado samples were synthesized in a high-pressure toroid-type chamber at an initial pressure of 8.0 GPa and a temperature of 1800‐ 2000 K in 12 s. The mass of the resulting polycrystal was 0.8 carat. We used MGOSCh graphite as the carbon material. In this study, we also used ultrafine powders (UDPs) that were obtained by the plasmochemical method and had the following characteristics: nickel and molybdenum (MIKhM) with an average particle size of 100 nm and an oxygen content of 3 and 5%, respectively;