Study On The Composition-Structure-Performance Relationship Of CCTO-Based Composite Dielectric Materials

CaCu₃Ti₄O₁₂?CCTO?ceramics have a giant dielectric constant.With the development trend of miniaturization of electronic products,high dielectric properties are urgently needed,which makes CCTO giant dielectric constant materials promising in the field of small electronic components.However,the relatively high dielectric loss of CCTO and the sensitivity of the giant dielectric constant to the process have become two major factors limiting the practical application of CCTO.Therefore,systematic research on the mechanism and law of dielectric properties of CCTO ceramics,as well as process exploration,development and optimization of CCTO ceramic properties will have a profound impact on its application.According to the current research status of CCTO ceramics,in order to improve the dielectric properties of CCTO,CCTO ceramics are prepared by solid-phase method.The composites of CCTO dielectric ceramic materials,metal oxide doping modification,and the introduction of additives to the structure and dielectric performance of CCTObased ceramics was studied.It shows.?1?CCTO is sintered at 1040? for 2h,room temperature to 600?,600? to 900?,900? to 1040? heating rate is 4?/min,3?/min,2?/min after sintering pure CCTO has a cubic phase perovskite structure,with perfect grain growth,uniform size,no abnormal crystallization,and good compactness.?2?The BNBT?CCTO composite system produces a second phase,and the second phase is most likely a copper barium titanate.The metal oxide doping modification and the introduction of additions did not change the phase composition of CCTO,and still maintained a stable cubic phase structure.?3?The composite system,metal oxide doping modification and the additives all changed the grain morphology of CCTO.The composite system,metal oxide doping is caused by the solid solution phenomenon during sintering,resulting in lattice distortion;The additives are due to the effect of liquid surface tension during sintering on the crystal growth.?4?The BNBT?CCTO composite system improves the dielectric constant while increasing the dielectric constant,but it does not reduce the loss significantly.When the doping amount of Fe₂O₃ exceeds 4% mol,CCTO achieves higher dielectric temperature stability;Mn O doping reduces loss at low temperature,but it inhibits dielectric constant;Al₂O₃ doped CCTO ceramic electrical constant is significantly improved,the loss is significantly reduced,and the dielectric temperature stability is high.When B₂O₃ and SiO₂ are added,the dielectric constant of CCTO is greatly improved,and the loss is lowered remarkably.?5?By comparison,the additives are more effective in improving the dielectric properties.The B₂O₃ is more effective than SiO₂ in improving the overall dielectric properties of CCTO.Among them,when the amount of B₂O₃ added reaches 8%mol,the dielectric constant is the highest value of 309859?140??,the dielectric constant at 45? is 60416,higher than that of pure CCTO at each temperature;in contrast,when the addition of B₂O₃ is 2% mol,dielectric loss at 45? is 0.07 and the dielectric constant is 81078.