抄録
Tungsten bronze structured Ba-rich Sr0.3Ba0.7Nb2O6 (SBN30) and Sr-rich Sr0.7Ba0.3Nb2O6 (SBN70) ceramics were synthesized by a solid state reaction and the microstructure evolution as a function of sintering time at 1400oC was studied. The synthetic temperature of SBN70 phase was higher than that of SBN30, and the temperature was proportional to the ratio of Sr/Ba. When the samples are sintered for 2 h, an intermediate phase was produced in SBN70 whereas a single phase was obtained in SBN30. However, both SBN70 and SBN30 showed normal grain growth with a uniform microstructure. Prolonged sintering up to 60 h developed abnormal grain growth in SBN70, while a uniform microstructure still maintained in SBN30. The generation of abnormal grain growth in SBN70 was explained due to an inhomogeneity induced liquid phase formation during the elimination of the intermediate phase.
