Joint resistances between two parallel high Tc superconducting tapes

Abstract

Eight different types of joining between two parallel high Tc superconducting (HTS) tapes were prepared and current-voltage ( -) characteristic curves were investigated at 77 K, liquid nitrogen temperature. Contact resistances of joint parts with 25 mm in length were estimated from -curves. Lowest contact resistance among eight samples having different types of joining was 0.497 . The best joining method is to do crossly joining with HTS tapes on two parallel HTS tapes after filling solder paste into their gap. In this case, lowest joint resistance was 0.15 at 77 K and 0.05 at 28 K. Joule heat of a joint sample generated at 30 K and at 100 A was calculated 0.492 mW. Also, in -curve of samples crossly joined with HTS tapes, it was found that joint resistance does not depend on variation of magnetic fields (0 7000 G) at 77 K. From consideration of Joule heat generation, such joining method is available for fabricating the field winding of superconducting rotating machine.

Experimental Investigations on the Critical Current of the Jointed Bi-2223/Ag HTS Tapes

“…The conventional method adopted in engineering practice is to join Z. Yan ( ) · H. Li · H. Shao · R. Wu · Y. Wang School of Electrical Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031, P.R. China e-mail: yzm@home.swjtu.edu.cn superconducting tapes by the resistive-joint method [1][2][3][4][5][6][7][8]. A crucial problem for the superconducting magnet operation in the persistent current mode is to make a joint with extremely low resistance between superconducting multifilamentary wires, whose resistance is an important parameter to evaluate the superconducting magnet performance.…”

“…Previous work on resistive joints between superconducting tapes has been aimed at reducing the joint resistance of the jointed tapes [1][2][3][4][5][6][7]. Of particular relevance are the works of T. Fukuzaki et al [6], a joint resistance of 1.27 × 10 −12 was obtained in Superconducting Joint.…”

A STUDY ON DEVELOPMENT OF JOINT BETWEEN PANCAKE MAGNETS MADE OF SS-LAMINATED Bi-2223∕Ag HTS TAPE

“…Some work on development of 'bridge joint' between two parallel SS-laminated BSCCO tape using Ag-sheathed BSCCO tape as a bridge has been reported [2 -3]. Bridge joining between two parallel Ag-sheathed BSCCO tapes has been reported in many research papers [4][5]. The overlap joint between two multifilamentary Ag-sheathed BSCCO tapes had been studied by some experimentalist [6].…”

Effects of uniaxial constant pressures on the joint properties of REBCO coated conductors

“…Among the joint processes, although soldering is a simple joint technique, resistance across the joint is high because it includes resistance of a soldering material, Ag layer and contact resistance of their interfaces. On the other hand, diffusion joining using Ag stabilizing layers, in which an Ag surface is put over the other in a face to face manner, can reduce the resistance across the joint without resistance of a soldering material [1][2][3][4][5][6]. Since some parameters in the Ag diffusion joint process may influence joint resistance, it is necessary to know about factors of the diffusion joint process.…”