Effects of excess K2O and processing conditions on the preparation of dense K(Ta1−XNbX)O3 ceramics

Dense ceramics of potassium tantalate niobates (KTa1−XNbXO3: X = 0.4) with a perovskite-type structure were prepared using powders including excess K2O and surrounding powder, and by applying vibration to the surrounding powder prior to firing. Excess K2O was inevitable for increasing density, and the use of surrounding powder reduced density fluctuation to a considerable extent. Furthermore, the powder including 8 mol% excess K2O fired at 1150 °C led to dense ceramics with relative density higher than 90%. The chemical composition of the resulting dense ceramics prepared here was confirmed to be that of a desired perovskite, KTa0.6Nb0.4O3. The KTa1−XNbXO3 ceramics obtained here showed almost the same dielectric properties as those prepared by delicate, costly, and time-consuming methods.