| 摘要 |
PURPOSE:To develop a Bi-Sr-Ca-Cu-O-based superconducting ceramic having a high critical temp. by calcining a mixture of SrCO3, CaCO3 and CuO to produce an Sr-Ca-Cu-O precursor, mixing low-melting-temp. Bi2O3 into the powder, press-forming the mixture and sintering the formed product at a specified temp. in a specified atmosphere. CONSTITUTION:SrCO3, CaCO3 and CuO are mixed in a specified molar ratio, the mixture is calcined at 900-1050 deg.C where the carbonates are decomposed to convert the SrCO3 and CaCO3 respectively into SrO and CaO, and an Sr- Ca-Cu-O precursor is formed together with CuO. The precursor is crushed, the low-melting-temp. Bi2O3 is added in a specified molar ratio and mixed, and the mixture is press-formed. The formed product is sintered in an atmosphere having 0.05-0.15atm O2 partial pressure at a temp. between the endothermic initiating temp. and endothermic peak temp. in the differential thermal analysis. Consequently, a superconducting ceramic having a high critical temp. of 105 deg.K and having a high content of Bi2Sr2Ca2Cu3O10 is produced. |
