Characteristics of Ag-doped BaTiO ₃ nanopowders prepared by spray pyrolysis

Pure and Ag-doped BaTiO ₃ nanopowders were prepared by spray pyrolysis. Precursor powders, prepared from a spray solution with citric acid and ethylenediaminetetraacetic acid (EDTA) as chelating agents, had large, hollow particles irrespective of Ag doping. Both pure and Ag-doped powders had partially aggregated particles after post-treatment at 900°C that could be easily milled to nanoparticles. The mean sizes of the pure and Ag-doped BaTiO ₃ particles were 75 and 91 nm, respectively. The Ag-doped particles were mainly of cubic BaTiO ₃ crystal structure, with small Ag phases observed. High-density BaTiO ₃ pellets were formed by sintering the powders at the low temperature of 1000°C. The silver was uniformly distributed in a tetragonal BaTiO ₃ phase without phase separation in the doped pellet. The dielectric constants of the pellets formed from the pure and Ag-doped BaTiO ₃ powders were 1826 and 2400, respectively.