Dielectric Behavior Of Perovskite Niobate Ferrite Oxides-barium Titanate Ceramics And Its Preparation

The molecular ventilation of the perovskite structure is ABO₃,which is widely used in various fields such as sensors,resistors and solid dielectric materials because of its excellent dielectric properties.In recent years,the Fe matrix composite calcium iron ore has become a hotspot in research of giant dielectric ceramic,In this article,through doping BaTiO₃ and A(Fe_0.5B_0.5)O₃?A=Ca?Sr?Zn?material to form A solid solution,by trying to doping modification for high dielectric constant,low dielectric loss,at the same time has a good temperature stability and frequency stability good ceramic material.Sr(Fe_0.5Nb_0.5)O₃ and Ca(Fe_0.5Nb_0.5)O₃ ceramic,lead-free piezoelectric ceramic systems of?1-x?Sr(Fe_0.5Nb_0.5)O₃-xBaTiO₃??1-x?Ca(Fe_0.5Nb_0.5)O₃-xBaTiO₃ and?1-x?Zn(Fe_0.5Nb_0.5)O₃-xBaTiO₃ were fabricated by a conventional solid-state reation in this paper.XRD results show that all ceramic as perovskite structure.The microstructure of ceramics was detected by scanning electron microscope,and the effect of microstructure on the ceramic dielectric properties was investigated.The dielectric spectrum,isothermal dielectric spectrum and impedance spectroscopy analysis the electrical properties and interface characteristics of the ceramic samples,the dielectric properties of the ceramic and the dielectric relaxation of conductive mechanism.The main research results are as follows:?1?Sr(Fe_0.5Nb_0.5)O₃ and Ca(Fe_0.5Nb_0.5)O₃ ceramic were prepared.By analyzing impedance spectra,the dc conductance activation energy of these two ceramics was mainly caused by the secondary ionization of oxygen vacancy.?2??1-x?Sr(Fe_0.5Nb_0.5)O₃-xBaTiO₃?x=0.1,0.2,0.3,0.4?[shorthand for?1-x?SFN-xBT]ceramic were prepared.At room temperature and 100?,the giant dielectric constant is greater than other Fe matrix composite calcium iron ore ceramics,and low dielectric loss,the giant dielectric constant is mainly originated from grain boundary layer capacitor effect,the dielectric behaviour of the ceramics can be explained in terms of the Maxwell-Wagner polarization.?3??1-x?Ca(Fe_0.5Nb_0.5)O₃-xBaTiO₃?x=0.3,0.4,0.5?[shorthand for?1-x?CFN-xBT]ceramic dielectric were prepared.It's near the temperature of 550K,the dielectric constant of 0.6CFN-0.4BT ceramic samples is higher??_r¹.9×10⁴ at 1kHz,?_r¹.3×10⁴ at 10 kHz?,The dc conductance in ceramics at high temperature is mainly caused by the migration of double ionized oxygen space.?4??1-x?Zn(Fe_0.5Nb_0.5)O₃-xBaTiO₃?x=0.1,0.2,0.3,0.4?[shorthand for?1-x?ZFN-xBT]ceramic were prepared.It's dielectric is not very good,the dielectric relaxation is mainly caused by the double ionization oxygen vacancy.?5?Comprehensive comparison,0.6Sr(Fe_0.5Nb_0.5)O₃-0.4BaTiO₃ ceramic and0.6Ca(Fe_0.5Nb_0.5)O₃-0.4BaTiO₃ ceramic dielectric performance are good.In the end of this paper,Sr(Fe_0.5Nb_0.5)O₃ and Ca(Fe_0.5Nb_0.5)O₃ ceramics were compared with the dielectric performance.The experiment results showed that the dielectric properties of the Fe matrix composite calcium iron ore were improved by doping with BaTiO₃.