Effects of Sintering Aids (Y³⁺, La³⁺ and Mg²⁺) on the Optical Transmittance of Translucent Alumina Ceramics

Translucent Al 2 O 3 ceramics were prepared by vacuum sintering using Y 3+ , La 3+ and Mg 2+ as sintering aids which were introduced via chemical precipitation. Effects of the sintering aids on microstructure, relative density and optical transmittance of the translucent Al 2 O 3 ceramics were investigated. The results show that the sintering aids are homogeneously dispersed in translucent Al 2 O 3 ceramics. The optimal amount of the sintering aid introduced is Mg 2+ (0.15wt%), Y 3+ (0.05wt%) and La 3+ (0.05wt%), and the corresponding sample shows the highest total forward transmittance (above 80% in the wavelength range of 350-800 nm). Moreover, the addition of Y 3+ could promote grain growth and decrease porosity, thus the optical transmittance of the translucent Al 2 O 3 ceramics is enhanced.