옥살산 공침법에 의한 Gd-Doped CeO2 분말의 합성 및 소결 특성

Abstract

GDC20(Ce0.8Gd0.2O1.9) powder was synthesized by oxalate co-precipitation and milling and its thermal decomposition, phaseformation, and sinterability were investigated. As-prepared precipitates were non-crystalline due to the milling process and completelydecomposed at 400oC. The powder calcined at 800oC for 2 h contained fine platy particles with an average size of 0.69m. Attritionmilling of the calcined powder for 2 h had a little milling effect, resulting in a slight decrease in the particle size to 0.45m. The milledpowder consisted of small spherical primary particles and some large particles, which had been agglomerated during calcination. Dueto the excellent sinterability of the powder, sintering of the powder compacts for 4 h showed relative densities of 78.7% at 1000oCand 97.8% at 1300oC, respectively. Densification was found to almost complete at temperature above 1200oC and a dense andhomogeneous microstructure was obtained. A rapid grain growth occurred between 1200oC and 1300oC. Grains in 0.1~0.5m sizesat 1200oC grew to 0.2~2m and their size distribution became broader at 1300oC.