Solid solutions formation in Sr-K-Ca-Na-Cu-O system

The synthesis and some experimental results of the new system: (Sr, K)(1-x) (Ca, Na)(x)CunO2+/-z. are shown. The series of polycrystalline samples with x up to 1.0 (n = 1,2) were prepared by solid-state reaction at different t emperatures (750-990 degrees C), in air and at ambient pressure below melt temperature. Single-phase solid solutions are observed for 0.0 less than or equal to x less than or equal to 0.5 at 750 degrees C (n = 1) and for 0.0 less than or equal to x less than or similar to 0.1 at 780 degrees C (n = 2 ). Both single phases are isostructural to the Cu2SrO3 compound, with an or thorhombic unit cell. The compositions in the range 0.6 less than or equal to x less than or equal to 1.0 (n = 1) have different crystalline structure s and those in the range 0.2 less than or equal to x less than or equal to 0.5 (n = 2) show the presence of non-reacted CuO. Also, characterization st udies by scanning electron microscopy and differential thermal analysis are shown. (C) 2000 Elsevier Science B.V. All rights reserved.