The effect of refinement of carbon-substituted MgB2 filling powder using various starting powders on the microstructure and critical current density of ex situ processed superconducting tapes
The effect of refinement of carbon-substituted MgB2 filling powder using various starting powders on the microstructure and critical current density of ex situ processed superconducting tapes
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DOI：
10.1088/0953-2048/27/3/035002
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发表时间：
2014-03
影响因子：
3.6
通讯作者：
H. Fujii;K. Ozawa;H. Kitaguchi
中科院分区：
文献类型：
--
作者：
H. Fujii;K. Ozawa;H. Kitaguchi
研究了用不同的Mg粉和B粉制备的国产碳取代MgB 2（MBC）填充粉的细化对用PIT技术非原位制备的Fe包覆MgB 2带材的显微结构和临界电流密度（Jc）的影响。当使用细镁粉时，自制MBC粉末含有大量MgO作为主要杂质相，而使用粗镁粉显著减少MgO的形成。这与起始B粉末无关。MgO作为孤立的颗粒和片状物存在于MgB 2微晶内。弱酸能部分溶解MgO，强酸几乎能完全溶解MgO。当使用烧结态MBC粉末时，带材的Jc性能很差。然而，通过用酸溶液精制这些粉末，它们显著增强。用低成本B粉制备的MBC微粉的质量与用高成本B粉制备的MBC微粉的质量相当。使用这些粉末的带材的Jc值在4.2 K和10 T下达到约6 kA cm-2。
We have studied the effect of refinement of homemade carbon-substituted MgB2 (MBC) filling powders prepared by using various commercially available Mg and B powders on the microstructure and critical current density (Jc) of Fe-sheathed MgB2 tapes fabricated through an ex situ process in a powder-in-tube (PIT) technique. The homemade MBC powders contained a substantial amount of MgO as a main impurity phase when using fine Mg powder, whereas the use of coarse Mg powder significantly reduced the formation of MgO. This was independent of the starting B powder. The MgO was present as isolated particles and platelets inside MgB2 crystallites. Weak acid could dissolve the MgO partially, whereas strong acid could dissolve it almost completely. When using the as-sintered MBC powders, the Jc properties of tapes were very poor. However, they were remarkably enhanced by the refinement of these powders with the acid solutions. The quality of the refined MBC powder prepared with low-cost B powder was comparable to that prepared with high-cost B. The Jc values of tapes using these powders reached about 6 kA cm−2 at 4.2 K and 10 T.