Diamonds for Use in Abrasive Tools

The development of technological processes for obtaining diamond powder is of industrial interest as a basic material in products for roughing and finishing surfaces, like in the polishing of ornamental rocks. This work investigates the influence of iron, as a doping agent, in association with the graphite to diamond transformation, which occurs during high pressure and high temperature synthesis in the presence of NiMn as a catalyst -solvent metallic alloy. Diamond synthesis was carried out at 4.3 GPa of pressure and 1300 C using a reactive mixture with 1:1 ratio of graphite and Ni-Mn alloy powders doped with up to 5% of Fe. The results indicated that that diamonds produced in the presence of Fe are more friable with increasing broken percentage of crystals. The higher growth speed is apparently the responsible for the defects that reduces the crystal strength. The results of the bond retention test demonstrate clearly that the textured diamond particles are more likely to shear rather than to be pulled out from the metal matrix.