抄録
We examined the preparation condition of ceria (CeO2) powders through homogeneous precipitation at 90°C and the effect of its morphology on sintering. The synthesized powder had different morphology depending on the condition in homogeneous precipitation method using hexamethylenetetramine (HMT). The coalesced spherulic powder with ca. 0.1μm size was obtained under the condition of Ce concentration of 0.05M with 0.3-0.5 M HMT. In the case of 0.1M Ce solution, the rod-like particles and fibers of CeO2 were obtained. For the synthesis of dense cerium oxide ceramics by pressureless sintering, the starting powders with spherulic shape were useful. The relative density of ceramics was 93% after sintering at 1400 °C for 1h in air. At 1500°C, the oxygen release in CeO2 was assumed. A sintering temperature of 1400°C can be applied for forming CeO2 ceramic by using the spherulic powders through the homogeneous precipitation at the concentration of 0.05 M Ce and 0.3-0.5M HMT.
