Microstructure and high critical current of powder-in-tube MgB2
Microstructure and high critical current of powder-in-tube MgB2
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DOI：
10.1063/1.1561572
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发表时间：
2003-03-17
影响因子：
4
通讯作者：
Mueller, FM
中科院分区：
文献类型：
--
作者：
Serquis, A;Civale, L;Mueller, FM
我们报告直流传输和磁化测量的临界电流密度，J（c），和微观结构分析的MgB2线制造的粉末管法（PIT）使用商业MgB2粉末与5原子。%的Mg粉末作为镁的额外来源添加，不锈钢作为护套材料。我们确定了一个薄弱环节的行为，在作为绘制的电线与微裂纹的存在。通过适当的热处理，由于过量Mg促进的再结晶过程，我们可以将J（c）提高一个数量级以上，这导致消除了我们的大部分微裂纹。相反，不适当的退火条件导致由于Mg的不均匀损失而导致的连接性恶化。晶粒尺寸和孔隙率在确定PIT MgB2中的J（c）中仅起次要作用。(C)2003年，美国物理学会。
We report dc transport and magnetization measurements of the critical current density, J(c), and microstructural analyses of MgB2 wires fabricated by the powder-in-tube method (PIT) using commercial MgB2 powder with 5 at. % Mg powder added as an additional source of magnesium and stainless steel as a sheath material. We identify a weak-link behavior in the as-drawn wire associated with the presence of microcracks. By appropriate heat treatments, we can increase J(c) by more than one order of magnitude due to a recrystallization process promoted by the excess Mg, which results in the elimination of most of our microcracks. In contrast, inappropriate annealing conditions result in a deterioration of connectivity due to an inhomogeneous loss of Mg. Grain size and porosity play only a secondary role in determining J(c) in PIT MgB2. (C) 2003 American Institute of Physics.