Subsolidus phase equilibria of coexisting high-Tc Pb-2223 and 2212 superconductors in the (Bi, Pb)–Sr–Ca–Cu–O system under 7.5% O2

Abstract

The subsolidus phase relationships of the high-Tc 2223 superconductor in the (Bi, Pb)–Sr–Ca–Cu–O (BSCCO) system have been examined at 810–820 °C. All experiments were carried out at ambient pressure in a 7.5% O2 (92.5% Ar) atmosphere. Eleven phases were found to exist in equilibrium with the 2223 phase. These 11 phases include CuO and 10 oxide solid solutions. From among these phases, a total of 48 five-phase combinations including the 2223 and 2212 phases were investigated experimentally, and 16 equilibrium assemblages were found which define a multicomponent compositional space corresponding to the 2223 + 2212 solid-state compatibility region. The subsolidus data form a partial basis for future investigation of the Pb-2223 primary phase field.