The Effect Of Bismuth-based Composite Perovskite Doping On The Dielectric Properties Of BaTiO₃ Ceramics

With the rapid development of electronic technology,people have higher and higher requirements for electronic equipment,especially MLCC can maintain high and stable dielectric constant at high and low temperature.BaTiO₃（BT）has been extensively studied and applied to capacitor applications for many years due to its good dielectric properties and environmentally friendly.Nevertheless,pure BT ceramics have three phase transitions,leading to the anomaly of the three dielectric,which limits their further applications in the electronic information industry.In order to enhance the thermal stabilities of BaTiO₃ ceramics,one of effective methods is formatting solid solutions with other perovskite compounds.The doping as an effective way to improve the material performance in electroceramics has been used in this paper.These solid solutions of（1-x）BaTiO₃-xBi(Li_0.5Nb_0.5)O₃（BT-BLN）,（1-x）BaTiO₃-xBi(Ni_0.5Sn_0.5)O₃（BT-BNS）,（1-x）BaTiO₃-xBi(Mg_0.5Sn_0.5)O₃（BT-BMS）,(Ba_1-xBi_0.33xSr_0.67x)(Ti_1-xBi_0.67xV_0.33x)O₃（BBSTBV）,(Ba_1-xBi_0.5xSr_0.5x)(Ti_1-xBi_0.5xTi_0.5x)O₃（BBSTBT）,(Ba_1-xBi_0.5xSr_0.5x)(Ti_1-xBi_0.5xSn_0.5x)O₃（BBSTBS）,(Ba_1-xBi_0.5xSr_0.5x)(Ti_1-xBi_0.5xZr_0.5x)O₃（BBSTBZ）were synthesized by the traditional solid state reaction technique.Furthermore,the phase evolution,microstructure,impedance spectroscopy,dielectric properties and ferroelectricity of ceramics were also investigated systematically.（1）With increasing x values,the tetragonal phase decreased gradually of BT-BLN,BT-BNS,BT-BMS,BBSTBV,BBSTBT and BBSTBZ ceramics,and transformed to pseudo-cubic phase.（2）（1-x）BT-xBLN（0.02≤x≤0.1）ceramic system.From the results of the study:dense microstructure was observed.High relative permittivityε_r（¹750）,small thermal-stability of relative permittivityΔε/ε_25°C5°C values（±15%）in a large range of temperature from-60°C to 160°C of 0.9BT-0.1BLN ceramics.（3）（1-x）BT-xBNS（0.02≤x≤0.1）and（1-x）BT-xBMS（0.02≤x≤0.12）ceramic system.From the results of the study:dense microstructure was observed.Highε_r（¹838）,77 in a large range of temperature from-60°C to 140°C of 0.9BT-0.1BNS ceramics.The best properties with a stable relative permittivity（ε_r,²918）,the thermal-stability of relative permittivity(Δε/ε_25°C≤±15%)in a large range of temperature from-56 to 248°C of 0.9BT-0.1BMS ceramics.（4）BBSTBV and BBSTBT（0.02≤x≤0.2）ceramic system.From the results of the study:with the increase of x value,the grain size of the sample decreases gradually.BBSTBV ceramic system does not meet the requirements of X7R or X8R.When x=0.1,BBSTBT ceramics have higherε_r（²293）and smallΔε/ε_25°C5°C values（±15%）in a large range of temperature from-58°C to 151°C.（5）BBSTBS and BBSTBZ（0.02≤x≤0.1）ceramic system.From the results of the study:all the samples showed fine dense microstructures.When x=0.06,BBSTBS ceramics have higherε_r（¹3643）and smallΔε/ε_25°C5°C values（±15%）in a large range of temperature from-61°C to 210°C.When x=0.1,BBSTBZ ceramics have higherε_r（²116）and smallΔε/ε_25°C5°C values（±15%）in a large range of temperature from-70°C to 155°C.