Evolution of precursor powders prepared by oxalate freeze drying towards high performance Bi-2212 wires
Evolution of precursor powders prepared by oxalate freeze drying towards high performance Bi-2212 wires
复制标题
通过草酸盐冷冻干燥制备的前体粉末向高性能 Bi-2212 线材的演变
DOI：
10.1016/j.ceramint.2020.09.170
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发表时间：
2021
影响因子：
5.2
通讯作者：
Zhang Pingxiang
中科院分区：
文献类型：
--
作者：
Jin Lihua;Liu Guoqing;Xu Xiaoyan;Jiao Gaofeng;Zheng Huiling;Hao Qingbin;Zhang Shengnan;Li Chengshan;Zhang Pingxiang
采用草酸冷冻干燥（OFD）法制备了bi2sr2cacuox （Bi-2212）前驱体粉体。与传统方法相比，该方法缩短了加工步骤，从而提高了前驱体粉末的制备效率。采用x射线衍射、扫描电子显微镜和红外光谱对Bi-2212前驱体粉末和丝的物相、微观结构和超导性能进行了表征。四探针法。讨论了粉末的热性能、比表面积和粒径。结果表明，大的比表面积和小的粒径可以提高粉末的反应性和均匀性。这些性质有利于Bi-2212快速均匀的形成。可以得到高纯度的铋-2212结晶粉末，不含铋-2201相和碱土铜酸盐相。此外，掺有OFD粉末的多丝Bi-2212丝的微观结构良好，没有明显的气孔和较大的二次颗粒。因此，在4.2K自场下，Bi-2212导线获得了1619 A/mm2的高工程临界电流密度（Je）和7039 A/mm2的临界电流密度（Jc）。这表明草酸盐冷冻干燥法是大批量生产高性能Bi-2212焊丝的潜在候选方法
Bi2Sr2CaCu2Ox (Bi-2212) precursor powders were synthesized by the oxalate freeze drying (OFD) method. In comparison with the traditional method, the novel method could shorten the processing steps and thus improve the fabrication efficiency of precursor powder. The phase, microstructure and superconducting properties of Bi-2212 precursor powders and wires were characterized by X-ray diffraction, scanning electron microscopy and .four-probe method, respectively. The thermal behavior, surface area and particle size of powders were also discussed. The results indicated that large surface area and small particle size might improve the reactivity and uniformity of powders. These properties were beneficial for the rapid and homogeneous formation of Bi-2212. High-purity crystallized Bi-2212 powders without Bi-2201 and alkaline-earth cuprates phases could be achieved. Furthermore, multi-filamentary Bi-2212 wires with OFD powders showed good microstructures without noticeable pores and large secondary particles. Therefore, high engineering critical current densities (Je) of 1619 A/mm2 and critical current densities (Jc) of 7039 A/mm2 were obtained in Bi-2212 wires at 4.2K, self field. It indicated that the oxalate freeze drying method would be a potential candidate for the mass production of high performance Bi-2212 wires