PHASE-EQUILIBRIA IN THE SYSTEM BI2O3-PBO-SRO-CAO-CUO WITH SPECIAL REGARD TO THE (BI,PB)(2+X)SR2CA2CU3O10+D PHASE

Phase equilibria of the quasiquaternary system (Bi, Pb)(2)O-3-SrO-CaO- CuO in air were studied at 850 degrees C and 865 degrees C with specia l regard to the high-temperature superconducting phase (Bi,Pb)(2+x)Sr2 Ca2Cu3O10+d (2223 phase). The 2223 phase lies in equilibrium with a nu mber of nonsuperconducting phases and also with the superconducting ph ase (Bi, Pb)(2+x)Sr2CaCu2O8+d (2212 phase). The homogeneity region was found to be very limited. The Pb-solubility of the 2223 phase is stro ngly temperature dependent. In the following a section through the iso thermal tetrahedron with CuO, SrO, CaO and (Bi/Pb)(2)O-3 as components for CuO = 37 at. % at 850 degrees C and 865 degrees C is shown. In ad dition, the homogeneity region in dependence on Bi- and Pb-content as well as on Sr- and Ca-content is presented in a temperature range betw een 800 and 890 degrees C.