Hydrothermal synthesis of perovskite and pyrochlore powders of potassium tantalate
- 1 December 2002
- journal article
- Published by Springer Nature in Journal of Materials Research
- Vol. 17 (12) , 3168-3176
- https://doi.org/10.1557/jmr.2002.0458
Abstract
Potassium tantalate powders were hydrothermally synthesized at 100 to 200 °C in 4 to 15 M aqueous KOH solutions. A defect pyrochlore, Kta2O5(OH).nH2O (n≈ 1.4), was obtained at 4 M KOH, but at 7–12 M KOH, this pyrochlore was gradually replaced by a defect perovskite as the stable phase. At 15 M KOH, there was no intermediate pyrochlore, only a defect perovskite,0.85Ta0.92O2.43(OH)0.570.15H2O. Synthesis at higher KOH concentrations led to greater incorporation of protons in the perovskite structures. The potassium vacancies required for charge compensation of incorporated protons could accommodate water molecules in the perovskite structure.Keywords
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