| 摘要 |
PURPOSE:To obtain fine-grain high-purity alpha-Al2O3 of a low alkali content by heat treating Al(OH)3 to convert it into crystal-free amorphous alumina, which is then dipped in an aqueous soln. of an aliphatic lower carboxylic acid, washed, and calcined at a specified temp. CONSTITUTION:Al(OH)3 is converted into crystal-free amorphous alumina by heat treatment. This alumina is then dipped in an aqueous soln. of an aliphatic lower carboxylic acid such as citric acid, oxalic acid or acetic acid, washed, and calcined at 1,100-1,300 deg.C to obtain alpha-Al2O3 capable of being pulverized easily and finely to submicron region, exhibiting high sintering activity in manufacture of porcelain, and giving a sintered body with superior characteristics such as high density and high mechanical strength. This alumina is suitable for use as starting material for high aluminous porcelain with superior heat resistance, electrical insulating properties and mechanical strength for an ignition plug, electronic parts and other field. |
