Abstract
Ceramic powders of (1 − x)BaNb 2O 6– xSrNb 2O 6 (0 ≤ x ≤ 1) composition were prepared by solid-state reaction. Thermal analysis data revealed that SrNb 2O 6 was formed at a lower temperature, compared with BaNb 2O 6. Ba 1− x Sr x Nb 2O 6 mixtures show an intermediate thermal behaviour. For the samples thermally treated at 1000 °C/3 h, X-ray diffraction data pointed out single phase compositions for x = 0.4–0.6, which means that SrNb 2O 6 completely dissolves into BaNb 2O 6 lattice in this composition range The temperature increase at 1150 °C leads to partial decomposition and supplementary demixing phenomena for all the mixtures analyzed. At 1300 °C, solid-state reactions progress and a structural rearrangement occurs, so that the same phase composition identified at 1000 °C was found again. A slight increase of the isomorphy limit of SrNb 2O 6 into BaNb 2O 6 lattice was also noticed. Single-phase compositions were identified for the samples with x = 0.3–0.6.
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