Thermally stabilised superconductor - having anti-diffusion layer at filament-matrix interface

摘要

The superconductor consists of one or more superconducting filaments within a stabilising matrix, each filament being provided with an anti-diffusion coating which separates the filament from the matrix and prevents formation of brittle hard cpds. The coating is pref. of niobium, tantalum, vanadium, molybdenum or an alloy of two or more of these metals. The coating allows higher working temps. (550-1000 deg.C) to be used during prodn. of the superconductor so that (i) greater reductions and larger starting blanks can be used to give products several tens of km. in length; (ii) a metallurgical structure, which has a high redn. of area value (greater than 80%, so that very fine filaments can be formed on subsequent drawing) and which allows retention of the ductile beta phase on quenching, is obtained; and (iii) harder superconducting alloys, having high critical current characteristics leading to increased current densities in the final superconductor, can be used. The resulting superconductor has high electrical and thermal stability.