| 摘要 |
PCT No. PCT/JP92/01352 Sec. 371 Date Jun. 16, 1993 Sec. 102(e) Date Jun. 16, 1993 PCT Filed Oct. 16, 1992 PCT Pub. No. WO93/08138 PCT Pub. Date Apr. 29, 1993.A sintered alumina abrasive grain comprised of alpha-alumina crystals and a spinel crystalline phase which does not form a continuous phase but is in the form of discrete crystals which are deposited on triple points in alumina crystal boundaries and are substantially uniformly distributed over the abrasive grain. Preferably, the alpha-alumina crystals have an average particle diameter not larger than 1 micron, and the spinel crystalline phase is composed of alumina and an oxide of a metal selected from Ni, Mg and Zn.
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