REACTION PROCESS IN THE Bi-Pb-Sr-Ca-Cu-O SYSTEM

The reaction process of formation of the Bi-Pb-Sr-Ca-Cu-O superconductor by means of a three-step reaction method was studied by high-temperature X-ray diffraction meansurement and DTA technique. The 2212 phase began to form at about 740℃ from the mixture of the Bi-Pb-Sr-Ca-O precursor-CuO, and the 2223 phase at about 825℃. The 2212 phase melted incongruently to the 2201 phase and a liquid phase at about 875℃ and the 2223 phase melted a liquid phase at about 935℃. In the crystallization of the 2212 phase, strong c-orientation forms easily.