Abstract
In a ternary system of Al2O3-Y2O3-MgO, the porosity, in- line transmittance and grain growth of sintered body were studied. The results obtained were summerized as follows. (1) The optimum composition of ternary system to obtain high transmittance was Al2O3-0.1 wt% Y2O3-0.025-0.05 wt% MgO, and the in-line transmittance (thickness 0.5 mm, wave length 300-1100 mμ) of the sample sintered at 1700°C for 5 hrs in H2 was approximately 70%. (2) The contribution of Y2O3 addition to grain growth during sintering of Al2O3-MgO system was very small. (3) The sintering process to achieve translucent Al2O3 were believed to be different from those of other transparent ceramics. It was supposed that diffusional removal of vacancies in Al2O3 was accelerated by the addition of Y2O3 at near 1700°C, and it contributed to increase of transparency of Al2O3-Y2O3-MgO ceramic.
