| 摘要 |
PURPOSE:To better the critical current density (Jc) characteristic of a thallium group oxide superconductive wire-rod in a magnetic field by utilizing as the core part of the superconductive wire-rod a superconductor formed through the process of heat- treating powdered bodies each comprising an oxide of Ca or of Ca-Cu compounded with the powder of a thallium group oxide superconductor. CONSTITUTION:As a superconductor forming the core part of a thallium group oxide superconductive wire-rod is utilized powder comprising an oxide of Ca or of Ca-Cu, as represented by CaO, Ca2CuO3, CaCu2O3 and the like, added to the powder of a thallium group superconductor. In this case, the mutual pinning force of superconductive grains becomes strong because each CaO or the like is dispersed minutely in its semi- melted condition and further trapped in each of superconductive crystal grains by the peritectic reaction thereof while functioning as a restraint from forming a different phase in the crystal grain boundary of the superconductor when the superconductive grains forming the core part are sintered and heat-treated respectively at a comparatively high temperature, e.g. a range from 900 to 920 deg.C in order to be combined together. This can better the critical current density (Jc) characteristic of the superconductive wire-rod in a magnetic field. |
