| 摘要 |
PURPOSE:To produce alpha-alumina powder made of single crystalline particles of alpha-alumina having a polyhedral shape other than tri- to heptahedral shapes, a value of 0.5-30 as the ratio of diameter to height, a narrow particle size distribution, high purity of the alumina, a uniform compsn. in the particles and structural homogeneity. CONSTITUTION:Transition alumina and/or alumina stock convertible into transition alumina by heat treatment is fired in atmospheric gas prepd. by introducing at least one kind of gaseous halogen selected from among gaseous fluorine, chlorine, bromine and iodine into atmospheric gas by >=5vol.% of the total amt. |
