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

Dense ceramics of potassium tantalate niobates (KTa_1−XNb_XO₃: 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, KTa_0.6Nb_0.4O₃. The KTa_1−XNb_XO₃ ceramics obtained here showed almost the same dielectric properties as those prepared by delicate, costly, and time-consuming methods.