摘要
以金属硝酸盐为原料（氧化剂）,甘氨酸为络合剂（还原剂）,采用自燃烧法合成了Sr掺杂的稀土铁酸盐La0.7-xSrxNd0.3FeO3-δ（x为0.1、0.2、0.3）粉体. BET法测定了粉体的比表面积（SA）,采用XRD、TG-DSC、TEM、SEM测试技术研究了粉体的合成条件、晶体结构及样品的微观形貌. 结果表明,初级粉体900 ℃热处理2 h就可形成单一钙钛矿结构的固溶体. 随样品Sr含量的增大,粉体的比表面积逐渐减小,粒径逐渐增大;物相由正交晶系逐渐向立方钙钛矿相转变. 使用直流四端子法测试了中温范围（450～800 ℃）内烧结陶瓷体在空气气氛中的电导率. 结果显示,合成样品低温下的导电行为符合小极化子导电机制;1 300 ℃烧结2 h的La0.5Sr0.2Nd0.3FeO3-δ样品电导率最高.
Perovskite-type Composite Oxides of La0.7-xSrxNd0.3FeO3-δ（x =0. 1,0. 2, 0. 3） were synthesized by the auto combustion method with the metal nitrate as oxidizing reagent and glycine as reducing agent. The specific areas of the synthesized powders were measured by nitrogen adsorption method. The formation conditions, crystalline structure and microstructure of the samples were investigated with XRD, TG-DSC, TEM and SEM. The experimental results show that the single Perovskite-type phase was obtained ＇after the powders calcined at 900 ℃ for 2 h. The electrical conductivities of the ceramics were determined by four-probe DC method in the temperature range of 450 - 800 ℃ in air. The specific area of the species decreases and the particle size increases with the increase of Sr content, and the crystal system transforms from orthorhombic to cubic gradually. The conduction mechanism is attributable to the adiabatic hopping of small polarons. The La0.7-xSrxNd0.3FeO3-δ sample sintered at 1300 ℃ for 2 h shows the highest conductivity.
出处
《应用化学》
CAS
CSCD
北大核心
2006年第5期561-565,共5页
Chinese Journal of Applied Chemistry
关键词
阴极材料
掺杂稀土铁酸盐
电导率
cathode materials, doping rare earths ferrites, conductivity
