Ceramic samples Bi2ZnxMn1–xTa2O9.5–? were synthesized for the first time using the solid-phase synthesis method. It was established that the samples contain the main phase of cubic pyrochlore (sp. gr. Fd-3m) and an admixture of BiTaO4 of the triclinic modification (sp. gr. P-1), the amount of which is proportional to the manganese content in the samples.
The formation of impurities is associated with the distribution of part of the transition element ions into the cationic sublattice of bismuth (III). The unit cell parameter of the pyrochlore phase increases with increasing content of zinc ions in the samples from 10.4895(5) (x = 0.3) to 10.5325(5) ? (x = 0.7), obeying the Vegard rule. It has been shown that the formation of impurities in samples can be prevented by creating a deficiency of bismuth ions in the bismuth sublattice by an amount proportional to the ?-BiTaO4 content. In this way, single-phase pyrochlores Bi2–yZnxMn1–xTa2O9.5–? were synthesized, the parameter of which increases with increasing content of zinc ions in the samples from 10.4764(5) (x = 0.3) to 10.5122(5) ? (x = 0.7). According to electron scanning microscopy, ceramic samples are characterized by a low-porosity microstructure with unclear outlines of grain boundaries. As the zinc content in the samples increases, the porosity of the preparations decreases. Samples with a deficient bismuth sublattice are characterized by a more porous microstructure due to a decrease in the content of the low-melting component of the reaction mixture – bismuth (III) oxide.
Daria S. Chirkova – bachelor of Chemistry Department, Syktyvkar State University, Syktyvkar, Russia
Roman I. Korolev – senior lecturer, Department of Radiophysics and Electronics, Syktyvkar State University, Syktyvkar, Russia
Boris A. Makeev – Candidate Of Geological-Mineralogical sciences, researcher at the Laboratory of Mineralogy, Institute of Geology FRC Komi SC UB RAS, Syktyvkar, Russia
Nadezhda A. Zhuk – Candidate of Chemical Sciences, Associate Professor, senior researcher of Laboratory of Ceramic Materials Science, Syktyvkar State University, Syktyvkar, Russia
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