(Bi,Pb)/2212高温超导粉末合成及热力学过程研究

Study on Synthesis and Thermodynamics of(Bi,Pb)/2212 High Temperature Superconducting Powder

采用共沉淀法制备了(Bi,Pb)/2212高温超导粉末,利用X射线衍射(XRD)和差热分析(DTA)对粉末的成相热力学过程进行了研究。结果表明,在(Bi,Pb)/2212前驱粉共沉淀过程中,含有Bi3+、Pb2+、Sr2+、Ca2+、Cu2+等5种金属离子的混合硝酸盐溶液,其温度不同将会导致生成的草酸盐沉淀产物发生颜色变化。对两种颜色状态的粉末进行的ICP分析显示,不同温度下,深浅粉末其化学计量比没有明显变化。通过对两种粉末在不同的烧结热处理制度下其XRD的物相分析以及对原始粉末的差热分析结果显示:浅色粉成相速度快,在主相2212形成时,浅色粉的2201相的含量也明显低于深色粉。

（Bi,Pb）/2212 superconducting powder is synthesized by co-precipitation method. The thermodynamics process of phase formation is studied by X-ray diffraction （XRD） and differential thermal analysis （DTA）. It is found that the different temperatures of solution including Bi^3＋ ,Pb^2＋ ,Sr^2＋ ,Ca^2＋, and Cu^2＋ ions induce different colors of precipitation. The ICP analysis indicates that the stoichiometry calculations in the different color powders are nearly uniform. The XRD and DTA results show that the decomposition of cambridge blue powder is faster than that of the navy blue powder and the content of 2201 phase is lower than that of navy blue powder.