Hamano Kenya    Ota Shizutoshi    Ozaki Yoshiharu

(Japan)

Abstract: In this paper, the influence of rare earth metal oxides on the sintering performance of alumina is studied from the measurement of shrinkage and the observation of microstructure. The added rare earth metal oxides hinder the densification of oxy aluminum sintering during the heating process from room temperature to 15000℃. However, when the temperature is kept at 1500°C, Sm₂O₃ and Er₂O₃ promote sintering, while Y₂O₂ and La₂O₃ Prevent sintering. When sintered at a temperature above 1700℃, all rare earth metal oxides promote the sintering of alumina. Especially when Er₂O₃ is added, a sintered body with the highest density can be obtained. Because the blank of this kind of alumina rare earth metal oxide system does not form a liquid phase at low temperature, and is not solid-solved in general, the alumina rare earth metal oxide and its reaction properties are accompanied by composite oxidation during the firing process. Diffusion of ions generated by the substance, volume change, and the state of being present between corundum particles as the second phase, etc., can all be considered to be the main factors affecting the densification of alumina sintering. It can also be observed that all the added samples produce abnormal particle growth at a temperature 50 -100 ℃lower than the eutectic temperature of alumina and composite oxide. When the eutectic temperature is higher than the eutectic temperature, due to the difference in wettability between the liquid phase and corundum particles produced, the organization structure is greatly affected.

Keywords: rare earth metal oxide, alumina sintering performance, shrinkage, microstructure