Dielectric properties and microstructures of non-reducible high-temperature stable X9R ceramics

New X9R dielectrics based on the precursors of (1-x)BaTiO(3-)xLiTaO(3) (BT-xLT) compositions and containing no lead and bismuth constituents were successfully prepared in this study. After sintering at 1150-1250 degrees C in a reducing atmosphere of 97%N-2-3%H-2, major phases including BaTiO3 and Ba2LiTa5O15 and a minor phase of Li2TiO3 were identified in the sintered ceramics. The intensities of the XRD peaks corresponding to the Ba2LiTa5O15 phase rose with the increasing x value in the precursors. The grain sizes of the sintered ceramics appeared to fall in the range between 0.3 and 0.5 mu m and slightly increased with the x value of the BT xLT ceramics. The best composition in term of dielectric properties was found in the BT-0.25LT ceramic, which was marked with a dielectric constant of 895, tan delta of 1.01% and 7.1%, TCCs of -3.04% and -14.80%, and electrical resistivities of 9.9 x 10(12) and 1.6 x 10(12) Omega cm, respectively at 25 degrees C and 200 degrees C. (C) 2013 Elsevier Ltd. All rights reserved.