Low-temperature synthesis and characterization of complex perovskite (Ca0.61, Nd0.26)TiO3-(Nd0.55, Li0.35)TiO3 nanopowders and ceramics by sol-gel method

A sol-gel process was adopted to synthesize nanopowder with composition of (1 - x)(Ca-0.61. Nd-0.26)TiO3-x(Nd-0.55, Li-0.35)TiO3 which was used to prepare the dielectric ceramics. As x <= 0.8, pure solid solution phase with GdFeO3-type perovskite structure could be obtained by calcining the xerogels at 500 degrees C. At x = 0.6, the particle size calculated from the transmission electron micrograph of powder was in the range of 30-50 nm. Ceramics prepared by the nanoparticles at 1150 degrees C exhibited good dielectric properties with dielectric constant (epsilon(r)) of 93.4, a Qxf value of 7115 GHz and tau(f) value of 0 ppm/degrees C, which have great improvement in Qxf value and decreased the sintering temperature compared with the ceramics synthesized by solid-state method. HRTEM images showed superstructure, indicating that the solid solution phase with ordering crystal structure is helpful to the dielectric properties improvement. (c) 2010 Elsevier B.V. All rights reserved.