Abstract: Al.sub.2 O.sub.3 -Er.sub.2 O.sub.3 ceramic abrasive grains comprising a second phase consisting of aluminum oxides and erbium oxides in the form of reaction products surrounding a first phase and the first phase exclusive of the second phase and substantially consisting of alpha alumina only, the size of the crystal grain consisting of two phases being below 1 micron, which are obtained by a sol-gel process wherein erbium precursor is incorporated before sintering in an amount of 0.05-0.4 wt % in a form of Er.sub.2 O.sub.3, which is suitable for lapping composition, grinding wheel, grinding disc and coated abrasive articles.

Abstract: Sintered aluminous abrasive grains having a density of at least 95% of theoretical density and having an alpha alumina crystal size of smaller than one micron. Which are obtained by drying and crushing a lithium containing alumina dispersion and sintering the crushed objects at 1100.degree.-1500.degree. C., said abrasive grains have the strength and hardness equal to or higher than conventional abrasive grains, superior properties in grinding resistance and wear resistance and superior self-sharpening property in course of grinding.