中文摘要：

采用以尿素为燃料的低温燃烧法一步合成了电解质粉末 Ce0.8 Gd0.2 O1.9（GDC），通过 XRD、TG-DSC、BET、FESEM等手段对合成粉体进行了物相测定、热分析、比表面积测定和形貌观察，并考察了粉体的烧结性能。结果表明，尿素-硝酸盐干凝胶自蔓延燃烧点火温度约为279.0℃。通过工艺参数的有效设计，经过低温燃烧过程即可直接得到立方萤石结构的纯相GDC粉体，该粉体为粒径在20~60 nm的类球形颗粒，粒子间虽有微弱的软团聚，却具有较高的烧结活性，在1300℃仅需烧结2 h 即可达到95.2%的相对密度。该温度比固相法制备该粉体的烧结温度至少降低300℃。

英文摘要：

Gadolinia doped ceria（Ce0.8 Gd0.2 O1.9 ,GDC）was a promising candidate material for electrolyte of in-termediate temperature solid oxide fuel cell（IT-SOFC）.Single-phase and ultrafine GDC powders were directly synthesized by low-temperature combustion synthesis using urea as fuel,nitrates as oxidants.XRD,TG-DSC, BET and FESEM were employed for the phase identification,the evolution behavior of the dried gel precursor, BET specific surface area measurement and morphological observations of the obtained powders,which sinter-ability of the GDC powder was studied.The TG-DSC result showed that the igniting temperature of urea-nitrate mixture gel was about 279.0 ℃.The results showed that the GDC powder with a pure cubic fluorite-type structure can be directly and rapidly synthesized through self-propagating low-temperature combustion proces-ses under the properly selected reaction conditions.The GDC powder particles with nearly spherical shape and weakly aggregated was in the range of 20-60 nm.The powders have good sinterability in the experiment and the sintered specimens with relative density was 95.2 % can be manufactured at 1 300 ℃ for 2 h under simply pro-cessing conditions.It was 300 ℃ lower than the sintered temperature of the powders derived from conventional solid reactions.