KOH处理法固相合成钙钛矿型氧化物Ba_(1.0)Co_(0.7)Fe_(0.2)Nb_(0.1)O_(3-δ)

Synthesis of Perovskite Oxides Ba_(1.0)Co_(0.7)Fe_(0.2)Nb_(0.1)O_(3-δ) by Solid-Solid Reaction with KOH Treatment

采用固相反应法以KOH室温预处理后的BaCO3,CoCO3,Fe2(C2O4)3.5H2O和Nb2O5混合原料,在空气或氮气气氛中合成了立方钙钛矿相复合氧化物Ba1.0Co0.7Fe0.2Nb0.1O3-δ粉体,并用合成粉体制备了透氧膜片。利用XRD和SEM等手段研究了合成温度和焙烧气氛对合成粉体相转变和形貌的影响。KOH预处理得到的前驱体在N2气中于1173K焙烧10h合成了立方相Ba1.0Co0.7Fe0.2Nb0.1O3-δ的粉体,与在空气中焙烧相比合成温度降低250K。利用前驱体在1073K焙烧10h所得粉体在空气中烧成了透氧膜片。讨论了烧成温度对膜显微结构的影响,在空气中于1373K保温10h制备的膜表断面非常致密,满足透氧膜工作的气密性要求。

Cubic perovskite-type composite oxide powder of Ba1.0Co0.7Fe0.2Nb0.1O3-δ （BCFNO） was synthesized by a solid-solid reaction with the starting mixing powder of BaCO3, CoCO3, Fe2 （C2O4）3 ·5H2O and Nb2O5 pre-proeessed by KOH at room temperature. The influence of calcination temperature and atmosphere on phase structure and morphology of the assynthesized powder was investigated with X-ray diffraction and Scanning Electron Microscopy techniques. The results showed that calcination in a N2 atmosphere could lower down the formation temperature of the cubic phase powder by 250 K comparing with calcination in air. The oxygen permeable membranes were prepared using the powder synthesized at 1073 K in air. The microstructure of the membranes was examined with respect to sintering temperature. It was found that sintering at 1373 K for 10 h could produce dense membranes, which satisfied the gas impermeability requirement of the oxygen permeable membranes.