| 摘要 |
PURPOSE:To readily obtain a superconductor having the constant critical temperature and >=100K by mixing the respective raw materials of Bi, Sr, Ca and Cu compounds at a specified element ratio and calcining the resultant mixture at a specific calcining temperature and holding time. CONSTITUTION:Raw materials are mixed, calcined and sintered to produce a Bi-Sr-Ca-Cu based superconductor. In the process, operation is carried out as follows. That is the respective raw materials of Bi, Sr, Ca and Cu compounds are mixed so as to provide 1.25, 1.00, 1.00 and 1.50 element ratio of Bi, Sr, Ca and Cu and calcining of the resultant mixture is carried out at 850-870 deg.C temperature for >=10hr holding time. If the above-mentioned calcining temperature is increased to >=870 deg.C, it is not preferable, since not only the raw materials are melted without retaining the original shape of the obtained compact but also the critical temperature of the superconductor is rapidly reduced. Conversely, if the temperature is reduced to <850 deg.C, it is not preferable, since the calcined compact will sometimes assume no superconductivity. |
