SrBi4Ti4O15 powder was synthesized by conventional solid state synthesis （ CS ） and molten salt synthesis （ MSS ） . MSS method can synthesize plate-like SrBi4Ti4O15 at lower temperature （900℃） than CS method. P...SrBi4Ti4O15 powder was synthesized by conventional solid state synthesis （ CS ） and molten salt synthesis （ MSS ） . MSS method can synthesize plate-like SrBi4Ti4O15 at lower temperature （900℃） than CS method. Plate-like form becomes more distinct when the synthesis temperature increases. This would help cause the grain orientation of the ceramics after sintering. The sintered samples of MSS had grain orientation at （0,0, 10） plane. The degree of （0,0,10） grain orientation F was 62.1% . Hot pressing made （0,0,10） grain orientation more distinct （ F = 85.7% ）. The microstructures of the sintered samples were detected by SEM. Due to the grain orientation the density of samples fabricated by MSS was lower than that of prepared by CS.展开更多
The structure and properties of Mg-doped SrBi4Ti4O15（SBT） were dicussed. Mg substitution into SBT had two possibilities states with the dopant amount variety. Mg cation substituted mostly into Sr^2＋ and the amount ...The structure and properties of Mg-doped SrBi4Ti4O15（SBT） were dicussed. Mg substitution into SBT had two possibilities states with the dopant amount variety. Mg cation substituted mostly into Sr^2＋ and the amount proportion was 68.11%.Mg ion will substitute into Ti ion site in perovskite layer when the doping amount increases. Polarization increases sharply when x=0.1 and then decreases becauses of the domain pinning. The Curie temperature of Mg-doped SBT is about 300 ℃ and there is a broad diffuse phase transition near Tc with a flat peak near the Ta of SBT.展开更多
Lanthanum doped bismuth layer structured ferroelectrics （BLSFs） Ca1 - x LaxBi4 （Ti0.9W0. 1 ）4O15 （ x = 0, 0.2, 0.3, 0.4, 0.6） ceramics were prepared by solid-state reaction method. X-ray diffraction （XRD） patt...Lanthanum doped bismuth layer structured ferroelectrics （BLSFs） Ca1 - x LaxBi4 （Ti0.9W0. 1 ）4O15 （ x = 0, 0.2, 0.3, 0.4, 0.6） ceramics were prepared by solid-state reaction method. X-ray diffraction （XRD） patterns showed that single phase was formed when x = 0 - 0.6. The effects of La^3＋ doping on dielectric, piezoelectric and ferroelectric properties of Ca1-xLaxBi4（Ti0.9W0.1）4O15 ceramics were studied. Ca0.7La0.3Bi4（Ti0.9W0.1）4O15 ceramic had optimal properties, its dielectric constant was 166.85, dielectric loss was 0.0063, piezoelectric strain constant was 11 pc·N^-1, remanent polarization was 18.1μC·cm^-2 and coercive field was 118 kV·cm^-1. SEM micrographs showed that the grains of CaBi4Ti4O15-based ceramics were plate-like. The results of energy spectrum analysis （EDS） showed that La^3＋ incorporation could increase Bi/Ca ratio.展开更多
SrBi2-χNdχNb2O9(χ=0,0.1,0.2 and 0.4)bismuth layer-structured ferroelectric ceramics were prepared by the solid-state reaction sintering method.The accurate position of Nd element in SrBi2-χNdχNb2O9 ceramics was d...SrBi2-χNdχNb2O9(χ=0,0.1,0.2 and 0.4)bismuth layer-structured ferroelectric ceramics were prepared by the solid-state reaction sintering method.The accurate position of Nd element in SrBi2-χNdχNb2O9 ceramics was determined by the X-ray Rietveld method and Synchrotron radiation X-ray absorption fine structure(XAFS)technology.The partial substitution of Nd 3+ for Bi 3+ leads to the decrease in the distortion of NbO6 octahedron for SrBi2-χNdχNb2O9 ceramics and also lowers the piezoelectric properties of SrBi2-χNdχNb2O9 ceramics.Meanwhile,the temperature coefficient of resonant frequency(TCF)decreases when Nd element partially replaces Bi element in SrBi2-χNdχNb2O9 ceramics.展开更多
文摘SrBi4Ti4O15 powder was synthesized by conventional solid state synthesis （ CS ） and molten salt synthesis （ MSS ） . MSS method can synthesize plate-like SrBi4Ti4O15 at lower temperature （900℃） than CS method. Plate-like form becomes more distinct when the synthesis temperature increases. This would help cause the grain orientation of the ceramics after sintering. The sintered samples of MSS had grain orientation at （0,0, 10） plane. The degree of （0,0,10） grain orientation F was 62.1% . Hot pressing made （0,0,10） grain orientation more distinct （ F = 85.7% ）. The microstructures of the sintered samples were detected by SEM. Due to the grain orientation the density of samples fabricated by MSS was lower than that of prepared by CS.
基金Funded by the Natural Science Foundation of China (No. 50472016, 50502027)the main project of the Ministry of Education (MOE) of China and the Chenguang Science Plan of Wuhan (No. 200750731268)
文摘The structure and properties of Mg-doped SrBi4Ti4O15（SBT） were dicussed. Mg substitution into SBT had two possibilities states with the dopant amount variety. Mg cation substituted mostly into Sr^2＋ and the amount proportion was 68.11%.Mg ion will substitute into Ti ion site in perovskite layer when the doping amount increases. Polarization increases sharply when x=0.1 and then decreases becauses of the domain pinning. The Curie temperature of Mg-doped SBT is about 300 ℃ and there is a broad diffuse phase transition near Tc with a flat peak near the Ta of SBT.
文摘Lanthanum doped bismuth layer structured ferroelectrics （BLSFs） Ca1 - x LaxBi4 （Ti0.9W0. 1 ）4O15 （ x = 0, 0.2, 0.3, 0.4, 0.6） ceramics were prepared by solid-state reaction method. X-ray diffraction （XRD） patterns showed that single phase was formed when x = 0 - 0.6. The effects of La^3＋ doping on dielectric, piezoelectric and ferroelectric properties of Ca1-xLaxBi4（Ti0.9W0.1）4O15 ceramics were studied. Ca0.7La0.3Bi4（Ti0.9W0.1）4O15 ceramic had optimal properties, its dielectric constant was 166.85, dielectric loss was 0.0063, piezoelectric strain constant was 11 pc·N^-1, remanent polarization was 18.1μC·cm^-2 and coercive field was 118 kV·cm^-1. SEM micrographs showed that the grains of CaBi4Ti4O15-based ceramics were plate-like. The results of energy spectrum analysis （EDS） showed that La^3＋ incorporation could increase Bi/Ca ratio.
基金Project(20080440083)supported by China Postdoctoral Science FoundationProject(2007CB924901)supported by the National Basic Research Program of China+1 种基金Project(60677022)supported by the National Natural Science Foundation of ChinaProject(09ZR1409200)supported by the Natural Science Foundation of Shanghai,China
文摘SrBi2-χNdχNb2O9(χ=0,0.1,0.2 and 0.4)bismuth layer-structured ferroelectric ceramics were prepared by the solid-state reaction sintering method.The accurate position of Nd element in SrBi2-χNdχNb2O9 ceramics was determined by the X-ray Rietveld method and Synchrotron radiation X-ray absorption fine structure(XAFS)technology.The partial substitution of Nd 3+ for Bi 3+ leads to the decrease in the distortion of NbO6 octahedron for SrBi2-χNdχNb2O9 ceramics and also lowers the piezoelectric properties of SrBi2-χNdχNb2O9 ceramics.Meanwhile,the temperature coefficient of resonant frequency(TCF)decreases when Nd element partially replaces Bi element in SrBi2-χNdχNb2O9 ceramics.
