PURPOSE: To obtain a long size and narrow diameter wire material having the high quality by previously and locally heating the raw wire material, which is obtained by compression-molding a specific type oxide superconductive composition granule under the specific vacuum condition, at a specific temperature, and annealing the wire material which melted part is processed by a diameter reducing member having a specific inner diameter with a specific term.
CONSTITUTION: The sintered Bi-Sr-Ca-Cu-O type oxide superconductive composition granule is compression-molded in the pressure reduction atmosphere less than 10Torr to form the deaerated raw material. After heating that wire material at a temperature more than 700°C previously, the wire material is locally heated at a temperature more than the melting point under the oxide atmosphere. After passing the melted part through a diameter reducing member which inner diameter is less than 5mm, the melted part is solidified. Further, the solidified part is heated at a temperature more than 500°C in the oxide atmosphere to be annealed, it is solidified stably, and no air is left inside because of a narrow diameter. A long size and narrow diameter oxide superconductive wire material oxided sufficiently by annealing to have the sufficient superconductive characteristic and having the high flexibility, the high critical current density and the high quality is thus manufactured.
TOMINAGA HARUO
TOMOMATSU KAZUHIKO
AOYANAGI MAMORU
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