MANUFACTURE OF HIGH PERFORMANCE COMPOUND SUPERCONDUCTIVE MATERIAL BY POWDER METALLURGY

摘要

PURPOSE:To obtain Nb3Sn superconductive wire uniform in fine filament size and having a little tangling, by specifying difference between average grain diameter of Nb and grain diameter of each Nb in Cu-Nb sintered body reduction worked and Nb grain content in the sintered body after sintering and heat treating the sintered body. CONSTITUTION:Cu-Nb powder in which Nb grain content is 5wt%=CNb=25wt% is compacted. Next, the green compact is heat treated to e.g. 900 deg.C in vacuum to obtain Nb sintered body. Billet is prepd. from the body, then extruded to a prescribed diameter by hot hydrostatic extrusion, further the material is reduction worked by swaging, wire drawing. Next, Sn equivalent to Nb quantity in wire material is plated from outer part, and diffused by heat treatment to obtain Nb, Sn superconductive wire material. In this case, denoting the average grain diameter of Nb used for sintering as dm(mum), grain diameter of each Nb as (d), it is required to use Nb powder so that ¦d-dm¦=0.35dm is satisfied.