Compound superconducting wire and method for manufacturing the same.

摘要

A compound superconducting wire comprising a matrix of CuX alloy and a multiplicity of Z3X filaments embedded in the matrix in a spaced relationship so as not to come into contact with each other wherein X is Sn or Ga and Z3X is Nb3Sn or V3Ga, which is prepared according to an internal diffusion process from (1) a precursor wire comprising a Cu base metal matrix, a core of a base metal material X such as Sn arranged in the center portion of the wire and a multiplicity of filaments of a base metal material Z such as Nb arranged concentrically in layers around the core, in which the spacing between any adjacent filaments arranged in a boundary region of an epsilon -phase bronze layer having a certain radius from the center produced when the precursor is preheat-treated at a temperature of 300 DEG to 600 DEG C is made larger than the spacing between any adjacent filaments arranged in the other matrix regions so that the filaments do not come into contact with each other when heat-treated to convert the precursor into a superconducting wire; or (2) a precursor wire wherein a composite of a Cu base metal material and a base metal material X capable of forming an alloy with the Cu base metal material is used as a matrix without arranging a core of the base metal material X at the center, and a multiplicity of filaments of a base metal material Z are embedded in the composite in a spaced relationship. Since the filaments are prevented from contacting each other in the heat treatment step, the effective filament diameter is remarkably decreased, thus hysteresis loss is decreased to improve the stability of superconducting coils, and also the critical current density Jc and uniformity of the wire are improved.