Study on synthesis of self-sharpening diamonds using powder catalyst capsule

Abstract

Self-sharpening diamonds were synthesized using the mixture of water-atomized FeNi alloy and graphite powders as raw materials, which were reduced and purified, granulated, and then compressed to prepare powder catalyst capsule. The influences of some key parameters, such as size and oxygen content of the powder catalyst, ratio of the catalyst to the graphite powders, and compressed density of the powder catalyst capsule, on the size and morphology, conversion, and impact toughness (TI) of resultant diamonds were researched. It was shown that oxygen content of powder catalyst apparently influenced the morphology of diamonds, in which it should be controlled in the range of 0.08–0.1 wt%, and the production per time and TI increased with increase of powder catalyst in capsule, in which TI reached a maximum point when oxygen content of powder catalyst was 30 wt%. It was also shown that the production of diamonds increased greatly, while TI increased slightly, when compressed density of powder catalyst capsul...