焙烧气氛对柠檬酸溶胶-凝胶法合成混合导体SrFeCo0.5Oy的影响

用柠檬酸溶胶-凝胶法合成SrFeCo0.5Oy混合导体,研究了焙烧气氛对合成过程的影响.利用XRD和SEM研究了粉体样品的晶体结构组成和形貌,利用阿基米德法测定了块体样品的密度.结果表明:在氧气气氛中焙烧可以得到以钙钛矿相为主晶相的SrFeCo0.5Oy,粉体为片状,颗粒较小,而在氩气中焙烧得到的样品以正交相为主要成分,粉体为圆形球状,颗粒较大;在氧气中低温烧结的块状样品的密度低于在氩气中烧结的样品的密度.探讨了样品在不同气氛下焙烧的反应机理.

Effect of Calcining Atmosphere on Synthesis of Mixed Conducting Oxides SrFeCo0.5Oy by Citrates Sol-Gel Method

Mixed conducting oxides SrFeCo_(0.5)O_y was synthesized by citrates sol-gel method.The effect of calcining atmosphere on synthesis process of samples was studied.The crystal structure and morphology of calcined powders were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM), and the density of calcined bulk samples was determined by Archimedes law.The experimental results show that the predominant phase perovskite Sr-Fe-Co-O oxides was prepared by calcining in oxygen.The powder obtained has flake shape and the particle is smaller.The predominant phase orthorhombie Sr-Fe-Co-O oxides was prepared by calcining in argon.The powder obtained has sphere shape and the particle is bigger.The density of bulk samples sintered at lcw temperature in oxygen is smaller than that of in argon. The reaction mechanism of samples calcined in different atmosphere was also discussed.