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Synthesis and characterization of Ba(TI1-xZRx)O₃ nanopowders by an aqueous coprecipitation method
Xiangbang Cheng,Zhuo Li,Zhonghua Yao,Yang Liu,Zhiyong Yu,Minghe Cao,Hanxing Liu 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.6
In this study, single phase Ba(Ti1-xZrx)O3 (0 ≤ × ≤ 0.15) nanopowders have been synthesized successfully by an aqueous coprecipitation method at 85 oC without any further heat treatment. The lattice strain calculated by the Hall-Williamson method indicates that the broadening of the XRD peaks is primarily due to the size of particles not to the lattice strain. The increase of the lattice parameter indicates that Zr ions have entered the lattice and a solid solution was successfully obtained. Furthermore, the particle sizes calculated by the Sherrer formula from the XRD patterns are in agreement with the results of SEM and TEM images. The nanopowders obtained can be used to prepare Ba(Ti1-xZrx)O3 ceramics with a tailored grain size and homogeneous composition, and this is significant to investigate the size effect in Ba(Ti1-xZrx)O3 ceramics and understand the relaxor behavior thoroughly. In this study, single phase Ba(Ti1-xZrx)O3 (0 ≤ × ≤ 0.15) nanopowders have been synthesized successfully by an aqueous coprecipitation method at 85 oC without any further heat treatment. The lattice strain calculated by the Hall-Williamson method indicates that the broadening of the XRD peaks is primarily due to the size of particles not to the lattice strain. The increase of the lattice parameter indicates that Zr ions have entered the lattice and a solid solution was successfully obtained. Furthermore, the particle sizes calculated by the Sherrer formula from the XRD patterns are in agreement with the results of SEM and TEM images. The nanopowders obtained can be used to prepare Ba(Ti1-xZrx)O3 ceramics with a tailored grain size and homogeneous composition, and this is significant to investigate the size effect in Ba(Ti1-xZrx)O3 ceramics and understand the relaxor behavior thoroughly.
Effect of ZnO on the microstructures and piezoelectric properties of K0.5Na0.5NbO3 ceramics
Zhuo Li,Xiangbang Cheng,Zhonghua Yao,Yang Liu,Hanxin Liu,Minghe Cao 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.5
Lead-free ZnO added K0.5Na0.5NbO3 piezoelectric ceramics have been prepared by a conventional solid state process. The XRD results show that all the K0.5Na0.5NbO3 ceramics with various ZnO contents are single phase with an orthorhombic perovskite structure. The bulk density obtained by the Archimedes method indicates that the addition of ZnO improves the density of K0.5Na0.5NbO3 ceramics under the same sintering conditions. Especially, at a level of 1 mol% ZnO, the sample sintered at 1100 oC for 1h exhibits the highest bulk density (ρ = 4.28 g/㎤) and shows optimal piezoelectric properties, d33 = 135 pC/N and kp = 0.40. Lead-free ZnO added K0.5Na0.5NbO3 piezoelectric ceramics have been prepared by a conventional solid state process. The XRD results show that all the K0.5Na0.5NbO3 ceramics with various ZnO contents are single phase with an orthorhombic perovskite structure. The bulk density obtained by the Archimedes method indicates that the addition of ZnO improves the density of K0.5Na0.5NbO3 ceramics under the same sintering conditions. Especially, at a level of 1 mol% ZnO, the sample sintered at 1100 oC for 1h exhibits the highest bulk density (ρ = 4.28 g/㎤) and shows optimal piezoelectric properties, d33 = 135 pC/N and kp = 0.40.