【摘要】 通过钨锰铁矿预合成法制备了铌铁酸铅-钛酸铅(1-x)Pb(Fe1/2Nb1/2)O3-xPbTiO3(PFN-PT)铁电陶瓷。X-ray衍射(XRD)测量和密度测试表明,1 150℃烧结2.5 h制备的PFN-PT陶瓷呈现纯钙钛矿结构和较高的致密度。随着PbTiO3(PT)质量含量的增加,PFN-PT的晶体结构从三方相向四方相转变,伴随着晶胞体积的减小和钙钛矿结构四方性因子(c/a)的增大。PFN-PT陶瓷呈现明显的介电频率色散现象,随着PT含量的增加,介电常数最大值温度Tm/TC升高,介电响应从弥散、宽化的介电峰变得相对尖锐,介电损耗减小,频率色散现象减弱。MnO2掺杂有效地改善了PFN-PT陶瓷的介电性能。w=0.25%MnO2掺杂的0.66PFN-0.34PT陶瓷100 kHz的最大介电常数εm为13 254,室温介电损耗tanδ为0.003 63,饱和极化强度Ps为6.18μC/cm2,矫顽场Ec为1.1 kV/mm,压电应变常量d33为98pC/N。更多还原

【Abstract】 (1-x)Pb(Fe1/2Nb1/2)O3-xPbTiO3(PFN-PT) ferroelectric ceramics were prepared by the conventional ceramic processing via the wolframite precursor method.The X-ray diffraction(XRD) measurement and density measurement confirmed that the PFN-PT ceramics sintered at 1 150 ℃ for 2.5 h exhibited pure perovskite structure and high relative density.With the increase of the content of PbTiO3(PT),the crystal structure of PFN-PT changed gradually from the rhombohedral perovskite structure to the tetragonal perovskite structure,while the cell volume decreased and the tetragonality(defined as the ratio of the cell parameters c/a) of the perovskite structure increased.The PFN-PT ceramics exhibited apparent dielectric frequency dispersion.With the increase of the PT content,the temperature of dielectric maximum Tm/TC increased,the dielectric response character changed from diffused and broad dielectric peaks to relatively sharper ones,the dielectric loss decreased,and the frequency dispersion became weak.The doping of MnO2 improved dielectric property of the PFN-PT ceramics effectively,in which the values of dielectric constant maximum εm and room-temperature dielectric loss tan δ were 13 254 and 0.003 63,respectively,at 100 kHz,and the values of saturation polarization Ps,coercive field Ec and piezoelectric constant d33 were 6.18 μC/cm2,1.1 kV/mm and 98pC/N,respectively,of the 0.25% MnO2-doped 0.66PFN-0.34PT ceramics.更多还原