| 摘要 |
PURPOSE:To prevent the superconducting characteristics and prolong the usable period of a superconducting material having oxide superconductor layer, by treating the material in a state kept from the contact with air immediately after the production. CONSTITUTION:A powdery mixture produced by mixing e.g. Y2O3 powder, BaCO3 powder and CuO powder at molar ratios of e.g. 0.5:2.0:3.0 is calcined in air, crushed, pulverized with a ball mill, etc., and put into a cladding tube made of copper. Both open ends of the tube is sealed and the tube is subjected to forging and drawing to obtain a superconducting material (e.g. wire) having an oxide superconductor layer. The outer circumference of the superconducting material is covered with an insulating material such as coarsely woven sleeve made of ceramic fiber, heated in an atmosphere of oxygen gas flow and slowly cooled. An epoxy resin is impregnated in the gap between the sleeve and the copper clad to prevent the direct contact of the wire with air and the product is immersed in liquid nitrogen to keep the material from contacting with air. |
