Dielectric properties of fine-grained BaTiO3 ceramics doped with CaO

Fine-grained dielectric ceramics, i.e., of 0.2 mum grain diameter, were obtained using Ca-doped BaTiO3 powders consisting of particles 0.2 mum in diameter. The (Ba1-xCax)(m)TiO3 ceramics (x: 0-0.10, m: 1.003-1.009) showed a high dielectric constant and stable temperature dependence, which were provided by interfacial stress due to the grain boundary, even though the ceramics has no core-shell structure. The failure time under an accelerated life condition was remarkably improved with Ca doping, which may be caused by the decrease in BaTiO3 unit volume with Ca2+ at the Ba2+ lattice site, and Ca2+ acceptor ions at the Ti4+ site.