K0.5Bi0.5TiO3(KBT)nanocrystalline particles were hydrothermally synthesized from Bi(NO3)3·5H2O, TiO2 and KOH. The crystal phase, chemical composition and microstructure were characterized by XRD, XRF, Raman scatt...K0.5Bi0.5TiO3(KBT)nanocrystalline particles were hydrothermally synthesized from Bi(NO3)3·5H2O, TiO2 and KOH. The crystal phase, chemical composition and microstructure were characterized by XRD, XRF, Raman scattering spectroscopy and TEM. The results indicated that the products were pure perovskite structured K0.5Bi0.5TiO3 with chemical stoichiometry and perovskite structure. The TEM observation revealed that the particles possessed a feature of cubic shape and a nano-scale of about 40 nm. The KBT ceramics sintered at 1 040 ℃ from hydrothermal powders show higher density and better electric properties than that prepared by a solid-state reaction method.展开更多
用熔盐法合成铌酸钾钠(Na_(0.52)K_(0.48)NbO_3,N_(52)K_(48)N)陶瓷粉体,用传统固相烧结工艺制备N_(52)K_(48)N陶瓷。研究了熔盐含量和烧结温度对N_(52)K_(48)N陶瓷粉体及其所制备陶瓷的相结构、微观形貌及电学性能的影响。结果发现,熔...用熔盐法合成铌酸钾钠(Na_(0.52)K_(0.48)NbO_3,N_(52)K_(48)N)陶瓷粉体,用传统固相烧结工艺制备N_(52)K_(48)N陶瓷。研究了熔盐含量和烧结温度对N_(52)K_(48)N陶瓷粉体及其所制备陶瓷的相结构、微观形貌及电学性能的影响。结果发现,熔盐法在750℃就合成了单一钙钛矿结构的N_(52)K_(48)N陶瓷粉体;随熔盐含量增加,N_(52)K_(48)N陶瓷粉体粒径增大,粉体团聚现象明显减弱。当熔盐与反应物质量之比为1∶5,烧结温度T=1050℃时,所制备的N_(52)K_(48)N陶瓷具有优异的电学性能:压电常数d33=137 p C/N,机电耦合系数kp=32.6%,居里温度Tc=410℃,表明熔盐法是一种很有前途的铌酸钾钠陶瓷制备方法。展开更多
Lead-free piezoelectric ceramics （1-y）Bi0.5（Na1-xLix）0.5TiO3-yBaTiO3 with x=0-0.125 and y=0.02-0.12 were fabricated by a solid-state reaction process, and their dielectric, piezoelectric and ferroelectric properti...Lead-free piezoelectric ceramics （1-y）Bi0.5（Na1-xLix）0.5TiO3-yBaTiO3 with x=0-0.125 and y=0.02-0.12 were fabricated by a solid-state reaction process, and their dielectric, piezoelectric and ferroelectric properties were investigated. The results show that the addition of Li^＋ significantly improves the sintering performance and piezoelectric properties of the ceramics. X-ray diffraction （XRD） patterns indicate that the ceramics possess pure perovskite structure. At room temperature, the ceramics provide high piezoelectric charge constant d33 （up to 210 pC/N）, high planar electromechanical coupling factor kp （34.5%）, large remanent polarization Pr （up to 40 μC/cm^2）, and low coercive field Ec （3.0 kV/mm）, which indicates that （1-y）Bi0.5（Na1-xLix）0.5TiO3-yBaTi03 is a good lead-free piezoelectric ceramic.展开更多
Aim The piezoelectric properties and cytotoxicity of a porous lead-free piezoelectric ceramic for use as a direct bone substitute were investigated. Methodology Cold isostatic pressing （CIP） was applied to fabricate...Aim The piezoelectric properties and cytotoxicity of a porous lead-free piezoelectric ceramic for use as a direct bone substitute were investigated. Methodology Cold isostatic pressing （CIP） was applied to fabricate porous lithium sodium potassium niobate （Li0.06Na0.5K0.44） NbO3 specimens using a pore-forming method. The morphologies of the CIP-processed specimens were characterized and compared to those of specimens made by from conventional pressing procedures. The effects of the ceramic on the attachment and proliferation of osteoblasts isolated from the cranium of 1-day-old Sprague- Dawley rats were examined by a scanning electron microscopy （SEM） and metbylthiazol tetrazolium （MTT） assay. Results The results showed that CIP enhanced piezoelectricity and biological performance of the niobate specimen, and also promoted an extracellular matrix-like topography of it. In vitro studies showed that the CIP-enhanced material had positive effects on the attachment and proliferation of osteoblasts. Conclusion Niobate ceramic generated by CIP shows a promise for being a piezoelectric composite bone substitute.展开更多
文摘K0.5Bi0.5TiO3(KBT)nanocrystalline particles were hydrothermally synthesized from Bi(NO3)3·5H2O, TiO2 and KOH. The crystal phase, chemical composition and microstructure were characterized by XRD, XRF, Raman scattering spectroscopy and TEM. The results indicated that the products were pure perovskite structured K0.5Bi0.5TiO3 with chemical stoichiometry and perovskite structure. The TEM observation revealed that the particles possessed a feature of cubic shape and a nano-scale of about 40 nm. The KBT ceramics sintered at 1 040 ℃ from hydrothermal powders show higher density and better electric properties than that prepared by a solid-state reaction method.
文摘用熔盐法合成铌酸钾钠(Na_(0.52)K_(0.48)NbO_3,N_(52)K_(48)N)陶瓷粉体,用传统固相烧结工艺制备N_(52)K_(48)N陶瓷。研究了熔盐含量和烧结温度对N_(52)K_(48)N陶瓷粉体及其所制备陶瓷的相结构、微观形貌及电学性能的影响。结果发现,熔盐法在750℃就合成了单一钙钛矿结构的N_(52)K_(48)N陶瓷粉体;随熔盐含量增加,N_(52)K_(48)N陶瓷粉体粒径增大,粉体团聚现象明显减弱。当熔盐与反应物质量之比为1∶5,烧结温度T=1050℃时,所制备的N_(52)K_(48)N陶瓷具有优异的电学性能:压电常数d33=137 p C/N,机电耦合系数kp=32.6%,居里温度Tc=410℃,表明熔盐法是一种很有前途的铌酸钾钠陶瓷制备方法。
基金supported by the National Nat-ural Science Foundation of China (No 50572066)the Sichuan Provincial Department of Education, China (No2006A075)the Doctor Start-up Foundation of China West Normal University (No 06B059)
文摘Lead-free piezoelectric ceramics （1-y）Bi0.5（Na1-xLix）0.5TiO3-yBaTiO3 with x=0-0.125 and y=0.02-0.12 were fabricated by a solid-state reaction process, and their dielectric, piezoelectric and ferroelectric properties were investigated. The results show that the addition of Li^＋ significantly improves the sintering performance and piezoelectric properties of the ceramics. X-ray diffraction （XRD） patterns indicate that the ceramics possess pure perovskite structure. At room temperature, the ceramics provide high piezoelectric charge constant d33 （up to 210 pC/N）, high planar electromechanical coupling factor kp （34.5%）, large remanent polarization Pr （up to 40 μC/cm^2）, and low coercive field Ec （3.0 kV/mm）, which indicates that （1-y）Bi0.5（Na1-xLix）0.5TiO3-yBaTi03 is a good lead-free piezoelectric ceramic.
基金supported by the National Natural Science Foundation of China (59972020)
文摘Aim The piezoelectric properties and cytotoxicity of a porous lead-free piezoelectric ceramic for use as a direct bone substitute were investigated. Methodology Cold isostatic pressing （CIP） was applied to fabricate porous lithium sodium potassium niobate （Li0.06Na0.5K0.44） NbO3 specimens using a pore-forming method. The morphologies of the CIP-processed specimens were characterized and compared to those of specimens made by from conventional pressing procedures. The effects of the ceramic on the attachment and proliferation of osteoblasts isolated from the cranium of 1-day-old Sprague- Dawley rats were examined by a scanning electron microscopy （SEM） and metbylthiazol tetrazolium （MTT） assay. Results The results showed that CIP enhanced piezoelectricity and biological performance of the niobate specimen, and also promoted an extracellular matrix-like topography of it. In vitro studies showed that the CIP-enhanced material had positive effects on the attachment and proliferation of osteoblasts. Conclusion Niobate ceramic generated by CIP shows a promise for being a piezoelectric composite bone substitute.
