Quaternary system SrO-CaO-BaO-CuO at 950 °C: I. Phase relationships in the limiting ternary system SrO-CaO-CuO

Knowledge of the succession of phases in dependence on composition and temperature is essential in order to control the formation of pure superconducting thallium-based cuprates (Tl/Pb)mSr2Can−1CunOx. Mixtures (Sr/Ba)OCaOCuO are used as precursors in their elaboration. In the first stage of our investigation, the ternary system SrOCaOCuO has been reinvestigated at 950 °C, in order to determine precisely the phase relationships in the ternary subsystem. In the second stage, the study will be extended to the quaternary BaOSrOCaOCuO system. The present paper reports the results concerning the polyphased fields in the ternary system under isothermal conditions at 950 °C under 1 bar of oxygen. A comparison with literature data shows that new domains are observed. Solid phases mentioned in the literature are confirmed, but the observed three phases equilibria are not the same