La_(0.8)Ca_(0.2)CrO_3钙钛矿复合氧化物的GNP法合成与表征

Characterization of Perovskite-Type Composite Oxides of La_(0.8)Ca_(0.2)Cr_3 Synthesized by the Glycine-Nitrate Process

采用GNP(Glycine-Nitrate Process)法合成La_(0.8)Ca_(0.2)CrO_3初级粉料,研究甘氨酸用量对产物的晶体结构和显微形貌的影响,并测试烧结体的相对密度和电导率。研究结果表明,甘氨酸与金属离子的摩尔比(G／M^(n+))控制在2.0～2.5时可得到颗粒尺寸细小、均匀(100nm～200nm)的单相钙钛矿粉体,烧结温度为1350℃时样品的相对密度达到91.0％,测试温度为800℃时样品的电导率达到30.5 S．cm^(-1)。与常规固相法相比,GNP法制备的样品具有更好的烧结活性和导电性能。

Perovskite-type composite oxides of Lao.sCao.2CrO3 were synthesized by the Glycine-Nitrate-Process method （GNP）. The effect of the mole ratio of glycine to the total metal cation concentration （ G/M^n＋ ） on the crystalline structure and morphology of the combusted powders and the synthesized powders was investigated by XRD and SEM. The relative density and electrical conductivity of the sintered samples were measured by the Archimedes method and DC four-probe method, respectively. It is found that the G/M^n＋ in the range of 2.0～2.5 produce fine and homogeneous powders （100 nm-200 nm） with a pure perovskite structure. The relative density of La0.8Ca0.2CrO3 sintered at 1350℃ attains 91.0%, showing an electrical conductivity of 30.5 S.cml at 800℃. Compared with the sample made by the conventional solid state reaction method, that synthesized by the GNP method provides superior sinterability and electrical conduction properties.