Development of ex situ processed MgB2 condoctors with strong grain connectivity

2016 Fiscal Year Final Research Report

• Project/Area Number: 25420696
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Physical properties of metals/Metal-base materials
• Research Institution: National Institute for Materials Science
• Principal Investigator: FUJII Hiroki 国立研究開発法人物質・材料研究機構, 高温超伝導線材グループ, 主席研究員 (80354306)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: 二硼化マグネシウム / ex situ法線材 / 臨界電流密度特性 / 結晶粒間結合 / MgO層除去

Outline of Final Research Achievements

In order to improve grain connectivity in ex situ processed MgB2 conductors,we have made attempt to remove MgO layers on the surface of MgB2 grains. Among three methods,the dissolution in weak acid solutions, reduction by the addition of Ca compounds and mechnical removal through ball milling process, the most effective method was the mechanical removal. Althohgh this method is already studied by several authors, with paying attention to the highly reactive milled powders, the Jc value at 4.2 K and 10 T was doubled and the optimized heat-treatment temerature decreased by more than 100 degree, compared with the previously reported values.

Free Research Field

超伝導線材