| 摘要 |
PURPOSE:To obtain a superconductor, capable of exhibiting superconductivity at liquid nitrogen temperature or above and having stabilized characteristics from inexpensive materials by mixing powders of compounds respectively containing Sr, Ca, Bi and Cu at a specific ratio, calcining and sintering the resultant mixed powder by a specified method. CONSTITUTION:The objective superconductor is produced by the following steps (a)-(c); (a) the first step for mixing bismuth oxide powder with copper oxide powder to provide mixed powder, calcining the resultant mixed powder at a lower temperature than the sintering temperature and pulverizing the calcined mixture to afford processed powder; (b) the second step for mixing strontium compound powder with a calcium compound powder, calcining the obtained mixed powder at a lower temperature than the sintering temperature and pulverizing the calcined mixture to afford processed powder; (c) a step for mixing and pressurizing the processed powders obtained in the first and second steps to provide a compact and (d) sintering the compact at 830-880 deg.C in an oxidizing atmosphere to afford a sintered compact. The sintered compact consists of Bi, Sr, Ca, Cu and O and the atomic ratios of the metallic components are Sr:Ca=1:0.3-3, Bi:Cu=1:1.8-4 and (Sr+Ca):(Bi+Cu)=1:1-2. |
