采用Nb/Cu复合管作为外包套材料,通过原位法粉末装管工艺(PIT)制备了C掺杂MgB_2 /Nb/Cu线材.在高纯流动氩气保护条件下、650～950℃温度区间内烧结2h微观结构分析显示,通过该工艺制备的MgB_2/NbZr/Cu线材具有良好的晶粒连结性和较高的致密度.X射线衍射(XRD)分析表明在750℃左右可以生成纯度较高的MgB_2相,在低温和高温下烧结后均有杂相峰出现,并且高温烧结后所生成的相结构较为复杂.采用四引线法超导临界电流的测试结果表明,低温烧结后的线材具有超导电流传输性能,而当热处理温度超过750℃时,样品中的电流传输状态表现为正常电阻态.实验结果证实采用Nb作为原位法MgB_2超导线材的包套阻隔层时,成相热处理一般应该在低于750℃的温度下进行.
MgB_2 wires doping with amorphous carbon were fabricated through the in-situ powder-in-tube method by using Nb/Cu composite sheath. Short samples of MgB_2/Nb/Cu wires were sintered at 650～950℃ for 2h in flowing high-purity argon. The microstructure observation for wires showed that MgB_2/NbZr/Cu wires have better grain connectivity and higher density. X-ray diffraction (XRD) show that higher purity MgB_2 phase was acquired after heat-treatment at 750℃, the impurity phase was appeared at lower or higher temperature and the phase formation was more complicated at higher temperature. Critical current density (J_c) of the wires were measured in the different magnetic field by standard four probe method, the result show that the wires ambition the normal state when the heat-treatment temperature Higher than 750℃. This indicated that the MgB_2 wires should be heat-treatment at lower than 750℃ while using the Nb as the sheathing.
参考文献
| [1] | Nagamatsu J;Nakagawa N;Muranaka T;Zenitani Y;Akimitsu J .Superconductivity at 39 K in magnesium diboride[J].Nature,2001(6824):63-64. |
| [2] | Larbalestier DC;Cooley LD;Rikel MO;Polyanskii AA;Jiang J;Patnaik .Strongly linked current flow in polycrystalline forms of thesuperconductor MgB2[J].Nature,2001(6825):186-189. |
| [3] | H. Yamada;N. Uchiyama;H. Kumakura;H. Kitaguchi;A. Matsumoto .Superconducting Properties of Aromatic Hydrocarbon-Added Powder-in-Tube MgB{sub}2/Fe Tapes[J].IEEE Transactions on Applied Superconductivity: A Publication of the IEEE Superconductivity Committee,2007(2 Pt.3):2850-2853. |
| [4] | P Kovac;I Husek;T Melisek .MgB_2 composite wires with Fe, Nb and Ta sheaths[J].Superconductor Science & Technology,2006(6):600-605. |
| [5] | 闫世成,闫果,卢亚锋,周廉.Mg-B体系成相热力学研究[J].稀有金属材料与工程,2006(12):1892-1895. |
| [6] | C R M Grovenor;L Goodsir;C J Salter .Interfacial reactions and oxygen distribution in MgB_2 wires in Fe, stainless steel and Nb sheaths[J].Superconductor Science & Technology,2004(3):479-484. |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%