報告書番号

H09019

タイトル（和文）

限流器用Bi2223超電導厚膜の作製 ―焼成温度と焼成回数の選定―

タイトル（英文）

Preparation of Bi2223 superconducting thick films for a magnetic-shielding fault current limiter -Sintering temperature and numbers of sintering treatment-

概要 （図表や脚注は「報告書全文」に掲載しております）

電力系統における短絡電流を抑制するために，Bi2223超電導厚膜を用いた磁気遮へい型超電導限流器を開発している。66kV級磁気遮へい型超電導限流器の開発のために，小片試料によるBi2223超電導厚膜の臨界電流密度の向上，および，Bi2223超電導厚膜大型円筒体の作製技術の開発をそれぞれ実施してきた。MgO基板とBi2223超電導厚膜の接合強度を強めるために挿入したBi2212中間層は臨界電流特性に悪影響を及ぼすことが分かった。したがって，接合強度が強く，高い臨界電流密度を有するBi2223超電導厚膜の作製技術を開発しなければならない。そこで，ブラスト処理して表面を荒らした基材を用いることで，Bi2212中間層なしで接合力を強める方式についての検討を行った。この表面を荒らした基材上へのBi2223超電導厚膜の作製条件の中で，焼成温度と焼成回数の最適化を行った。その結果，最適焼成温度は850～860℃の間で，焼成回数は3回が適していることが明らかになった。

概要 （英文）

A magnetic shielding type superconducting fault current limiter using Bi2223 superconducting thick films has been developing to reduce the short-circuit current in electric power system. To develop the 60 kV-class magnetic shielding type superconducting fault current limiter, improvement of critical current density of Bi2223 superconducting thick films using short samples and development of production technique of a large cylinder using Bi2223 superconducting thick films have been individually carried out. It has been unfortunately found that a Bi2212 buffer layer inserted in order to enhance combination between the MgO substrate and the Bi2223 superconducting thick film are not suitable for high critical current density. Therefore, the production technique should be modified to obtain the large cylinder using high performance Bi2223 superconducting thick film. Among several ideas, the use of substrates with rough surface by blast treatment is chosen as a method of enhancement of combination without the Bi2212 buffer layer. This paper is described the optimization of a sintering temperature and numbers of sintering treatment in several preparation conditions for Bi2223 superconducting thick films on the rough surface substrates. As a result, it has been found that the appropriate temperature range of sintering is between 850 and 860 ºC and the sintering treatment of three times is enough for high critical current density.

報告者

キーワード