| 摘要 |
PROBLEM TO BE SOLVED: To improve superconucting characteristics, capable of utilizing strain induced orientated grain growth phenomena, controlling impurity formation, improving high current density and processability, by pressurizing a polycrystal of a specific yttrium-based superconductor. SOLUTION: In this yttrium-based superconductor, in order to prepare a polycrystal (finely crystal particle dense sintered compact, chemical formula Ba2 YCu3 CO7-y ) densified into >=95% theoretical density, having <=1μm particle diameter of constituent crystal particles, spray dried powder (0.05μm particle diameter) is molded, sintered at 750 deg.C under 1,000atm by HIP, pressurized by 10MPa maximum stress at 870-930 deg.C and at 1MPa/h stress applying rate under >=2MPa uniaxial stress (compression or tensile) to carry out orientated grain growth treatment to obtain a highly orientated texture of plate particles having approximately a uniform plane (ab), 10-20μm major axis diameter and 2-3μm minor axis diameter. Then the compact is subjected to post-annealing treatment (at 90 deg.C by no load under 1 atmospheric pressure oxygen at 500 deg.C for 40 hours) in a tress released state. |
