关键词: Ce0.8Gd0.2O2-d, 共沸蒸馏, 烧结, 纳米晶粒

Abstract: Reactive nanocrystalline Ce0.8Gd0.2O2-d (GDC) nanopowder has been successfully synthesized via a modified carbonate coprecipitation method. Azeotropic distillation treatment was applied to dry the carbonate precipitates, where the dehydration process was proved to be effective to alleviate hard agglomerate formation during high temperature calcination, as confirmed by the BET and FESEM characterizations. The results showed that after calcination at 600℃, the powder from the precursor with the azeotropic distillation treatment has a specific surface area of 49.0 m2/g, which is substantially higher than that of the powder from the precursor without the azeotropic distillation treatment. Sintering behavior of these two kinds of powder was investigated via dilatometry and isothermal sintering, and revealed that the powder from the precursor with the azeotropic distillation treatment showed better sintering activity, where uniaxially pressed compacts were sintered to over 98% of theoretical density at 1100℃ for 10 h. The superior sinterability was mainly attributed to the fact that azeotropic distillation treatment reduced the tendency of hard agglomeration formation for the as-synthesized powders, which allows to form green compacts in high green density with high homogeneity.

Key words: Ce0.8Gd0.2O2-d, azeotropic distillation, sintering, nano-sized particles