Abstract
Sol-gel processing of a solution of niobium and potassium ethoxides in methanol was used to prepare polycrystalline potassium niobate ceramic discs. Gel powders completely crystallized after only 2 h at 600 ° C. Crystallized powders were hot-pressed at pressures less than half of that required in conventional methods. Densities of up to 99% were achieved without encountering the common problem associated with the evaporation of the potassium oxide and subsequent formation of a stable second phase. The variation of dielectric constant with temperature was measured up to several degrees above the Curie temperature (ã420b ° C). Dielectric constants of dense samples were found to be more than one and one-half times greater than that of their single crystal counterparts.
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Nazeri-Eshghi, A., Kuang, A.X. & Mackenzie, J.D. Preparation and properties of KNbO3 via the sol-gel method. J Mater Sci 25, 3333–3337 (1990). https://doi.org/10.1007/BF00587695
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DOI: https://doi.org/10.1007/BF00587695