| 摘要 |
PURPOSE:To improve the critical temperature and the critical current density of an oxide superconductor such as Bi-Sr-Ca-Cu-O superconductor by hot-forging a sintered material having low density. CONSTITUTION:Powders of Bi2O3, SrO, CaCO3 and CuO are weighed at atomic ratios of 1.8-2.2 atoms of Bi, 2.0-3.5 atoms of Ca and 3.0-4.5 atoms of Cu based on 2 atoms of Sr. As necessary, the above powders are mixed with powders of PbO, K2CO3, Na2CO3, Li2CO3, etc. The mixed powder is formed and calcined in an oxidizing atmosphere at 840-855 deg.C to a sintered density of <=3.0g/cm<3>. The sintered product is subjected to hot-forging by heating at 800-850 deg.C under a pressure of >=50kg/cm<2>. The product is annealed by heating at 830-855 deg.C in an oxidizing atmosphere under normal pressure for >=10hr to obtain the objective oxide superconductor having high orientation degree of crystal particles, high density and a critical current density of >=5,000A/cm<2>. |
