权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Development in design technology of advanced MgB_2 wires for future electric device windings

未来电子器件绕组用先进MgB_2线材设计技术开发

基本信息

批准号：
16206032
负责人：
FUNAKI Kazuo
金额：
$ 31.87万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16206032/
关键词：
MgB_2 in-situ method ex-situ method critical current density AC loss thermal stability normal zone propagation conduction cooling パウダー・イン・チューブ法 MgB_2法 ex situ法常伝導伝播通電特性熱処理温度

项目摘要

Magnesium diboride, MgB_2, has a new metallic superconductor with a critical temperature about 20 K higher than Nb'll, one of usual metallic ones and furthermore a potential to develop low-cost advanced superconducting wires without liquid helium cooing because of the simple fabrication processes. Aim of the present study is to evaluate various properties of superconducting MgB_2 wires and to propose structural design for improving the electromagnetic and thermal properties and fabrication processes for the advanced structures. The main results in the study are summarized in the following.1) From a viewpoint of improving the transport property of superconducting MgB_2wires especially in high magnetic field, advanced methods were given for the in situmethod by addition of impurities and for the ex-situ method by controlling initial powders of MgB_2.2) As a candidate of long-scale low-AC-loss MgB_2 wires, composite wires with a CuNi sheath and Ta barriers for the filaments were successfu … More lly fabricated by the in-situ method with a gun-drill process and their AC losses were measured by a standardized pickup coil method. The results were reproduced by the usual theory of superconducting multifilamentary wires and, on the basis of the empirical study, structural design for the lower AC loss wires was proposed.3) For basic approach to quench analysis in future MgB_2 coils, normal zone propagation in the wires were experimentally studied by inducing an initial hot spot by a heater in liquid helium or under a conduction cooling condition, and the responses of the normal zone were well explained by theoretical thermal model with transient cooling effects. The stability in a large-capacity conductor with assembled16strands was tested by comparing the critical current of the conductor with that of the strands. The results suggest future MgB_2coils can be constructed with high stability and flexibility in the quench protection design.4) A conduction-cooling test coil with a100m-class MgB_2multifilamentary wire was successfully fabricated by a wind and react method. The characteristic tests with direct over current and alternating current were performed in a temperature rangebetween 15K and 30K. It was shown experimentally that MgB_2coils have a high stability margin because of the critical temperature higher than 30K. Less

二硼化镁（MgB_2）是一种新的金属超导体，其临界温度比常用的金属超导体之一Nb_11高20 K左右，而且由于其制备工艺简单，有可能发展出无需液氦冷却的低成本先进超导线材。本研究的目的是评估MgB_2超导线材的各种性能，并提出改善其电磁和热性能的结构设计和先进结构的制造工艺。主要研究结果如下：1）从改善MgB_2超导线材的输运性能，特别是在强磁场下的输运性能的角度出发，对添加杂质的原位法和控制MgB_2初始粉末的异位法提出了改进的方法。2）作为长尺寸低交流损耗MgB_2线材的候选材料，采用铜镍合金护套和钽阻挡层的复合丝， ...更多信息 Lly通过枪钻工艺的原位方法制造，并且通过标准化拾波线圈方法测量它们的AC损耗。3）为进一步研究MgB_2超导线圈的失超特性，通过在液氦中或传导冷却条件下用加热器诱导初始热点，对MgB_2超导线圈的法向区扩展进行了实验研究，考虑瞬态冷却效应的理论热模型很好地解释了正常区的响应。通过比较16股绞合大容量导线与股绞合导线的临界电流，对导线的稳定性进行了测试。研究结果表明，未来的MgB_2超导线圈可以在失超保护设计方面具有更高的稳定性和灵活性。4）采用缠绕反应法成功制备了100 m级MgB_2超导多芯线的传导冷却实验线圈。在15 ~ 30 K温度范围内进行了直流过电流和交流过电流特性测试。实验结果表明，MgB_2线圈的临界温度高于30 K，具有较高的稳定裕度。少