Quaternary system SrO-CaO-BaO-CuO at 950 °C: II. Phase equilibria related to the substitution Sr/Ba in (Sr/Ba)2Ca2Cu2Cu3O7 and (Sr/Ba)2CaCu2O5 samples

A partial study of the solid-solid equilibria in the quaternary system BaOSrOCaOCuO has been undertaken in order to determine the observed phases and their evolution when Ba is substituted for Sr in mixtures (Sr/Ba)2CaCu2Ox and (Sr/Ba)2Ca2Cu3Ox. The temperature was fixed at 9SO °C and samples were elaborated under 1 bar of flowing oxygen. It has been shown that two four-phased domains exist in this quantemary system, including the following phases: (Ba/Sr/Ca)CuO2, (Sr/Ca/Ba)2CuO3, (Sr/Ca/Ba)14Cu24Ox and Ba4CaCu3O8 substituted Sr/Ca for the one and (Ba/Sr/Ca)CuO2, (Sr/Ca/Ba)2CuO3, (Sr/Ca/Ba)24Cu24Ox and (Sr/Ca/Ba)CuO2 for the other.