ALPHA ALUMINA-BASED ABRASIVE GRAIN CONTAINING SILICA AND IRON OXIDE

摘要

Alpha alumina-based ceramic abrasive grain comprising, on a theoretical oxide basis, Al2O3, Fe2O3, and SiO2. The abrasive grain has a surface roughness height of greater than about 200 nanometers and a density of greater than about 3.50 g/cm3. Preferably, the alpha alumina-based ceramic abrasive grain has alpha alumina crystallites having an average crystallite size of less than about 0.5 micrometer (more preferably, less than about 0.3 micrometer). The presence of the SiO？2? in combination with Fe2O3 increases the amount of transgranular fracture of the abrasive grain, reduces the alpha alumina crystallite growth during sintering of the abrasive grain, dilates at least one of the unit cell dimensions of the abrasive grain, and generally improves the grinding performance of the abrasive grain. In another aspect, a method for making alpha alumina-based ceramic abrasive grain comprising on a theoretical oxide basis, Al2O3, and SiO2 is disclosed.