真空雰囲気で焼成したTiO₂を添加したAl₂O₃セラミックスの微構造と強度

抄録

Microstructure and mechanical strength of Al₂O₃-TiO₂ ceramics fired in vacuum were studied by X-ray powder diffractometry, scanning electron microscopy, and bending test method. Alumina powder compacts containing 0-4wt% TiO₂ were sintered at 1500-1700°C in vacuum (10^-3-10^-4Pa) and then annealed at 1300°C in air. The solid solubility of TiO₂ into Al₂O₃ increased with an increase in temperature in vaccum. Beyond the solid solubility limit, TiO₂ or Al₂TiO₅ existed in alumina matrix and restrained the grain growth of alumina. Vacuum-sintered bodies which had high solubilities of Ti were annealed in air. Excess Ti ion existing in Al₂O₃ grains diffused to the grain boundary, and then to the surface of the sintered body, and the annealing treatment slightly decreased the bending strength of sintered bodies.