Preparation of MgB2/Fe tapes with improved Jc property using MgH2 powder and a short pre-annealing and intermediate rolling process
Preparation of MgB2/Fe tapes with improved Jc property using MgH2 powder and a short pre-annealing and intermediate rolling process
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DOI：
10.1088/0953-2048/18/5/l01
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发表时间：
2005-05
影响因子：
3.6
通讯作者：
C. Jiang;H. Hatakeyama;H. Kumakura
中科院分区：
文献类型：
--
作者：
C. Jiang;H. Hatakeyama;H. Kumakura
采用短时间预退火和中间轧制工艺对MgH 2和B粉末制备的MgB 2/Fe带材进行了原位处理。未掺杂和10at.%掺杂的两种材料的Jc特性都比较好。通过这种改进的原位工艺，纳米SiC掺杂的MgB 2/Fe带材得到了很大的改善。在600 °C下预退火15 min并在中间轧制后在600 °C下进一步热处理1 h的样品中获得最佳Jc结果。在10 T和4.2 K下，SiC掺杂和非掺杂的带材在此最佳条件下的Jc值均提高了约80%。MgH 2在反应初期的分解会产生大量的裂纹和孔隙，在MgB 2形成之前，在带材中留下多孔芯。在我们改进的原位工艺中，MgH 2的分解在600 °C下在15 min内完成; MgH 2分解产生的孔隙和裂纹通过随后的轧制有效地消除。通过利用这种预退火和中间轧制工艺，最终带材的芯密度显著提高，这反过来又改善了MgB 2带材的Jc性能。
A short pre-annealing and intermediate rolling process was applied to in situ processed MgB2/Fe tapes prepared using MgH2 and B powders. The Jc properties of both the non-doped and 10 at.% nano-SiC-doped MgB2/Fe tapes were greatly improved by this modified in situ process. The best Jc results were obtained in the samples pre-annealed at 600 °C for 15 min and further heat treated at 600 °C for 1 h after the intermediate rolling. An enhancement of about 80% in Jc values in 10 T and at 4.2 K was achieved for both SiC-doped and non-doped tapes using this optimum condition. The decomposition of MgH2 at the early reaction stage would generate many cracks and pores, which leaves a porous core in the tapes before the formation of MgB2. In our modified in situ process, the decomposition of MgH2 was completed within a 15 min pre-annealing at 600 °C; the MgH2-decomposition-generated pores and cracks were effectively eliminated by the subsequent rolling. The core densities of the final tapes were significantly enhanced by utilizing this pre-annealing and intermediate rolling process, which in turn improved the Jc property of the MgB2 tapes.