A novel aqueous solution route to the low-temperature synthesis of SrBi2Nb2O9 by use of water-soluble Bi and Nb complexes

Powders of SrBi2Nb2O9 (SBN) were synthesized using an aqueous solution meth od from mixtures of all water-soluble compounds including Sr-EDTA, Bi-EDTA and Nb-citrate. Heating of a mixed aqueous solution with the molar ratio of Sr:Bi:Nb:citric acid=1:2:2:10 produced a pale-yellow gelatinous viscous ma tter without any precipitation, which was subsequently pyrolyzed at 300 deg rees C to give a powder precursor for SBN. The formation of a pure Perovski te ferroelectric SBN occurred when the powder precursor was heat-treated in air at temperatures higher than 650 degrees C. A fluorite SBN formed in th e 500-600 degrees C range, which appeared to act as an intermediate phase p rior to the formation of the Perovskite SBN. The environmentally beneficial aspect of the present aqueous solution route was briefly discussed. (C) 20 00 Elsevier Science S.A. All rights reserved.