Phase equilibria in the Bi-Sr-Co-O system: Towards the material tailoring of thermoelectric cobaltites

Phase diagram of the Bi-Sr-Co-O system in air atmosphere was experimentally determined. A number of samples with different Bi:Sr:Co compositions were prepared by solid state reaction and analyzed by X-Ray diffraction (XRD) to map thermodynamically stable ternary phases and their fields of stability. Previously published phase diagrams of quasibinary systems Bi-Co-O, Sr-Co-O and Bi-Sr-O were also used for the assessment of phase equilibria in the ambient temperature limit. Our phase diagram will be useful for the whole ceramic community working with bismuth strontium cobalt mixed oxides as well as for the development of highly-efficient thermoelectric materials.