| 摘要 |
PURPOSE:To prevent an evil influence caused by precipitation of second phase, etc., and to improve critical current density by specifying the ratio of the number of mols of Bi, Sr, Ca and Cu. CONSTITUTION:Raw material powder of oxides of Bi, Sr, Ca and Cu is blended, calcined and heat-treated in an oxygen-containing atmosphere to give a superconducting composition of oxide of Bi-Sr-Ca-Cu-O base satisfying the condition (a-4)<2>/0.02+(b-4.2)<2>/0.039+(c-4)<2>/0.01<1 when the ratio of the number of mols of Bi:Sr:Ca:Cu is a:b:10-a-b:c. The compound is at least partially melted, cooled and coagulated in an atmosphere containing Bi to give a superconducting material of oxide. |
