Promotion of phase formation and introduction of pinning centers in Bi based high Tc superconductors, and their applications to tapes and bulks

Bi基高温超导体中相形成的促进和钉扎中心的引入及其在带材和块材中的应用

• 批准号: 09355023
• 负责人: MAEDA Hiroshi
• 金额: $ 20.54万
• 依托单位: Kitami Institute of Technology (1999)Tohoku University (1997-1998)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09355023/
• 关键词: Bi2223 & Bi2212; V-doping; Ag-sheathed multifilamentary tape; Sr-V-O barrier; critical current density; a.c.loss; magnetic melt processing; crystal orientation; Bi2223; Agシース多芯線; Sr-V-O絶縁バリアー; Bi2212; 磁場中結晶育成; 酸化物高温超伝導体; 添加効果(V,Ir,Fe); 高温超伝

Bi oxide superconductors (Bi2212. Bi2223) are the most important candidates for practical use. For practical applications high critical current density Jc and low a.c.losses will be required.we found that a considerable amount of V added into Bi oxide superconductors greatly enhances the Bi2223 formation without any degradation of Tc. The added V exists as Sr6V2O11 (SVO) plate-like particles, which play an important role to promote the formation. Using V doped Bi2223 powder, we prepared Ag-sheathed tapes with monofilament and multifilaments by the powder-in-tube method. Jc values increase with increasing the V content up to 0.15 and this tendency becomes more and more conspicuous for multifilametary tapes. Furthermore, we prepared Ag-sheathed Bi2223 multifilamentary tapes with a layer of SVO barrier outside and inside each filament. The SVO barrier layers have no bad effects on the critical current density Jc of the tapes and decrease a.c.losses obviously. Jc increases obviously in the tapes with barriers both inside and outside each filament. Therefore, the SVO will be one of the important candidates for barriers to reduce a.c.losses.Magnetic melt processing (MMP) or crystal growth in high magnetic field have been applied to Bi2212 bulks and thick tapes in order to achieve high crystal orientation. For them no techniques have been developed so far. Magnetic field tends to orient Bi2212 grains with the c-axis parallel to it and the degree of texture increases notably with increasing the magnetic field. Therefore, the Jc values of Bi2212 bulks and thick tapes are improved obviously. This shows that MMP is a promising method to prepare Bi2212 bulks and thick tapes with high grain orientation and high Jc values.

Bi氧化物超导体（Bi2212、Bi2223）是实际应用中最重要的候选者。对于实际应用，需要高临界电流密度Jc和低交流损耗。我们发现，在Bi氧化物超导体中添加大量V可以极大地增强Bi2223的形成，而不会降低Tc。添加的V以Sr6V2O11(SVO)片状颗粒存在，对促进形成具有重要作用。采用V掺杂Bi2223粉末，采用管粉法制备了单丝和复丝银护套带。 Jc值随着V含量增加到0.15而增加，并且这种趋势对于复丝带变得越来越明显。此外，我们还制备了 Ag 护套 Bi2223 复丝带，每根丝的外部和内部都有一层 SVO 屏障。 SVO阻挡层对带材的临界电流密度Jc没有不良影响，并且明显降低了交流损耗。在每根细丝内外都有屏障的带材中，Jc 明显增加。因此，SVO将成为减少交流损耗的势垒的重要候选者之一。磁熔加工（MMP）或高磁场下的晶体生长已应用于Bi2212块体和厚带材，以实现高晶体取向。到目前为止，还没有为他们开发出任何技术。磁场倾向于使Bi2212晶粒定向为与c轴平行的方向，并且织构程度随着磁场的增加而显着增加。因此，Bi2212块体和厚带材的Jc值明显提高。这表明 MMP 是制备具有高晶粒取向和高 Jc 值的 Bi2212 块体和厚带材的一种有前途的方法。

项目成果

M.Yavuz,H.Maeda,L.Vance,H.K.Liu,S.X.Dou: "Phase development and Kinetics of high temperature Bi-2223 phase"Journal of Alloys and Compounds. 281. 280-289 (1998)

M.Yavuz，H.Maeda，L.Vance，H.K.Liu，S.X.Dou：“高温Bi-2223相的相发展和动力学”合金与化合物杂志。

竹内孝夫、根本善弘、前田弘、伊藤喜久男、井上廉、小菅通雄、湯山道也、和田仁: "V3Si 極細多芯超伝導線の微視的組織と電磁特性"日本金属学会誌(日本金属学会論文賞受賞). 62. 727-734 (1998)

Takao Takeuchi、Yoshihiro Nemoto、Hiroshi Maeda、Kikuo Ito、Ren Inoue、Michio Kosuge、Michiya Yuyama、Hitoshi Wada：《V3Si超细多芯超导线材的微观结构与电磁特性》日本金属学会学报（Japan Institute of Metals）最佳论文奖）62. 727-734 (1998)。

H.Maeda,P.X.Zhang,K.Watanabe,T.Matsushita and E.S.Otabe: "Fabrication and properties of Ag-sheathed Bi2223 tapes with Sr6V2O11 oxide barriers between filaments"Physica C. (in press).

H.Maeda、P.X.Zhang、K.Watanabe、T.Matsushita 和 E.S.Otabe：“细丝之间具有 Sr6V2O11 氧化物屏障的银护套 Bi2223 带的制造和性能”Physica C.（出版中）。

W.P.Chen,H.Maeda,K.Watanabe,M.Motokawa: "Introducing a melt processing into fabrication of Bi(Pb)2223 bulks"Advances in Superconductivity. (in press).

W.P.Chen、H.Maeda、K.Watanabe、M.Motokawa：“将熔融加工引入 Bi(Pb)2223 块体的制造”超导性的进展。

H.Maeda,P.X.Zhang,K.Watanabe,T.Matsushita and E.S.Otabe: "Jc properies of Ag-sheathed Bi2223 tapes with Sr-V-oxide barriers"Advances in Superconductivity. (in press).

H.Maeda、P.X.Zhang、K.Watanabe、T.Matsushita 和 E.S.Otabe：“具有 Sr-V 氧化物势垒的 Ag 护套 Bi2223 带的 Jc 特性”超导进展。