| 摘要 |
PURPOSE:To improve the critical temp. and current density of the semiconductor by incorporating an oxide consisting essentially of Bi, Sr, Ca and Cu, Ag and Pd into the total composition. CONSTITUTION:A starting material obtained by mixing Bi, Sr, Ca and Cu in the atomic ratio of 2:2:1:2 or 2:2:2:3 or the material, in which 10-30mol% of the Bi is replaced by Pb, is mixed with methanol and crushed in a ball mill, and the product is dried at 100 deg.C for 24hr. The material is placed on an alumina burning plate, calcined at about 800 deg.C for about 24 hr in the atmosphere using an electric furnace, then wet-crushed and dried. The powder for synthesis is placed on an alumina burning plate, heated at about 840 deg.C for about 50hr in a low-oxygen-pressure atmosphere at O:N=1:10 to obtain a bismuth-based superconductor. The material is wet-crushed and mixed with 10-35wt.% Ag (e.g. silver powder having 0.8mum average grain diameter) and 0.1-2wt.% Pd (e.g. Pd powder having 1.0mum average grain diameter), the mixture is pelletized at about 147MPa and sintered at about 840 deg.C for 10hr in the atmosphere to obtain the superconductor. |
