PURPOSE: To obtain a superconductive wire of an excellent mechanical strength and an excellent superconductive property by applying a diameter reduction process to a composite formed by filling at least either an oxide superconductor or a precursor of an oxide superconductor in a metal pipe while forging it with a die.
CONSTITUTION: Y2O3 powder, BaCO3 powder, and CuO powder are mixed at the ratio Y:Ba:Cu=1:2:3, to obtain a mixture powder, which is heated in the atmospheric ambiance at 700°C for 24 hours to carry out a temporary treatment. Then the temporarily heated powder is filled in a pipe made of Ag, and the resultant composite is processed for diameter reduction while forging in a cold condition by using a rotary swaging device A with a die 6, to reduce the diameter of the Ag pipe, from the outer diameter 10mm to 1.4mm, for example, step by step. In this diameter reduction process, the section reduction rate in one pass is set about 20%. In such a way, the powder can be pressed densely in the rate higher than the case of a drawing-out process using a die. As a result, when the heat treatment is applied to produce a superconductor, the elements are diffused easily inside the powder formation, and a superconductor wire of an excellent mechanical strength and superconductive property can be obtained.
KONO TSUKASA
SADAKATA NOBUYUKI
SUGIMOTO MASARU
NAKAGAWA MIKIO
AOKI SHINYA
KUME ATSUSHI
GOTO KENJI
USUI TOSHIO
