Phase Equilibria of the SrO–CaO–CuO System at 950°C in 1 atm of Oxygen and at 10 kbar

Abstract

Phase equilibria in the CuO‐rich (≥33% CuO) portion of the SrO–CaO–CuO system have been determined at 950°C in 1 atm of pure oxygen and at 10 kbar (1 bar = 105 Pa). Three solid‐solution series occur under these conditions. There is a complete solid solution between the Ca2CuO3 and Sr2CuO3 endmembers at both 1 atm and 10 kbar, as has been previously noted in experiments conducted in air. Another solid‐solution series extends continuously between SrCuO2 and (Sr0.38Ca0.62)CuO2 in 1 atm of oxygen, but is limited to between SrCuO2 and (Sr0.64Ca0.36)CuO2 at 10 kbar. At 10 kbar, more Ca‐rich phases in this solid‐solution series are not stable, but (Sr0.3Ca0.7)CuO2 and (Sr0.1–0.16Ca0.9–0.84)CuO2 are stable at 1 atm. The third solid‐solution series ranges between Srl4Cu24O38 and (Sr0.41CaO.59)14‐Cu24O38 in 1 atm of oxygen; the Ca‐rich limit of this solid solution changes only slightly to (Sr0.39Ca0.61)14Cu24O38 at 10 kbar.