1. Dense and single-phase KTaO$_{3}$ ceramics obtained by spark plasma sintering
- Author
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Féger, L., Giovannelli, F., Vats, G., Alves, J., Pignon, B., Salje, E. K. H., Monot-Laffez, I., and Nataf, G. F.
- Subjects
Condensed Matter - Materials Science - Abstract
Potassium tantalate (KTaO$_{3}$) is a promising material for dielectric applications at low temperature. However, dense and single-phase ceramics cannot be obtained by conventional sintering because of the evaporation of potassium that leads to secondary phases. Here, we demonstrate that spark plasma sintering is a suitable method to obtain dense and single-phase KTaO$_{3}$ ceramics, by optimizing three parameters: initial composition, temperature, and pressure. A 2 mol% K-excess in the precursors leads to a large grain growth and dense single-phase ceramics. Without K-excess, a small amount of secondary phase (K$_{6}$Ta$_{10.8}$O$_{30}$) is observed at the surface but can be removed by polishing. At 10 K, the dielectric permittivity is 4 times higher in the ceramic from the 2 mol% K-excess powder, because of the larger grain size. The thermal conductivity decreases with decreasing grain size and stays above the thermal conductivity of KNbO$_{3}$ ceramics., Comment: to be published in Journal of the European Ceramic Society
- Published
- 2023
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