| 摘要 |
PURPOSE:To obtain a superconductor capable of providing a superconducting state at liquid nitrogen temperature using inexpensive materials by mixing powders of a Bi oxide, Sr oxide, Ca carbonate and copper oxide, compression forming the mixed powders and calcining the resultant compact in an oxidizing atmosphere. CONSTITUTION:Powders of bismuth oxide, strontium oxide, calcium carbonate and copper oxide are mixed and simultaneously compression formed to provide a compact, which is then calcined at 830-880 deg.C in an oxidizing atmosphere to provide the aimed calcined compact consisting of Bi-Sr-Ca-Cu-O. The resultant calcined compact has atomic ratios of Sr:Ca=1:0.3-3, Bi:Cu=1:1.8-4 and (Sr+ Ca):(Bi+Cu)=1:1-2 of components in Bi-Sr-Ca-Cu-O forming the principal part. The critical temperature of a conventional superconductor using Y is about 90K; however, the temperature of the above-mentioned superconductor is about 105K. Since a superconducting phenomenon is caused at a higher temperature, a stable superconducting state can be maintained. |
