Microstructure Control And Performance Study Of PLZT Electronically Controlled Light Scattering Ceramics

Since Heartling et al.succeed in preparing the lead zirconate titanate(PLZT)electrooptic ceramics in 1972 in Sandy National Key Laboratory of the United States by using the hot pressing sintering process for the first time,the unique electro-optic effect has been gradually known to us all,especially the electronic controlled light scattering effect.That is,the incident light can arise strong scattering under the control of the external electric field,that making PLZT more widely used in image storage and display parts,and will be expected to be used in polarization independent high speed light modulators.However,due to the limitation of the ceramic preparation technology,the electronic light scattering effect of PLZT electro-optic ceramics is closely related to the grain size,the experimental process and the internal stress of the materials.Therefore,this paper systematically studies the regulation and annealing effect of the microstructures in the PLZT electro-optic ceramics through the doping of the crystal species and the annealing treatment of the finished products.First,the sol-gel chemical method was used to prepare the PLZT crystal with good activity and uniform fine particles.XRD was shown as perovskite structure,and the grain was arranged in ceramic materials to promote the growth of grain in the process of sintering.PLZT(8/68/32)electro-optic ceramics samples with uniform densification structure were prepared by hot pressing sintering process,and the effects of crystal doping content(0%,5%,10% and 15%)on the structure and properties of the materials were studied systematically.It is found that a stable perovskite structure is formed in the process of sintering,which is a typical cubic structure.With the increase of crystal doping content,the grain size shows an obvious trend of growth and the dielectric constant is also the same.The grain content has a great influence on the ferroelectric properties of the material.The material is a typical anti-ferroelectric return line and the wire is in a contraction state when the content of the material is low(0%-10%).When the high doping content(15%),the hysteresis loop of the material is fine ferroelectric return line,the residual polarization and coercive field obviously decrease,the ferroelectric behavior changes obviously,and the light scattering behavior and attenuation of the material are obviously improved.In order to further explore the influence of crystal seed,the influence of calcining temperature on PLZT electro-optic ceramics is continued.The selected crystal seed doping amount is 5%,the calcining temperature gradient is 550,600,700,750,800,850 and 900?.It is found that the calcining temperature of the seed is not produced at low temperature(550-850?)at low temperature.The influence of high temperature(900?)will produce heterogeneous phase,which will affect the material structure.The material is a typical anti-ferroelectric phase.The calcination temperature of crystal seeds has little effect on the material,and the residual polarization and coercive field are all low.The relative dielectric constant with seed calcination temperature at first increased and then decreased,dielectric temperature of Pukuan.The transmittance of materials is high,and the trend of transmittance is consistent with dielectric constant.The turning point is 650?.The experimental process also affects the properties of the material.In this experiment,the heat treatment annealing process was used to eliminate the internal stress produced in the process of sintering and mechanical processing,and the effect of annealing treatment on the properties of PLZT(8/68/32)electro-optic ceramics was discussed.After annealing,the highest phase transition temperature(Tm)phase of PLZT(8/68/32)moves in the direction of high temperature,and the relative dielectric constant increases with the increase of annealing temperature.Annealing treatment has significant influence on the ferroelectric properties of PLZT material.After annealing treatment,the residual polarization(Pr)and the coercive field(Ec)of the material are reduced,and the ferroelectric properties are weakened.Annealing treatment has a significant effect on the electro-optic properties of PLZT materials.After annealing,the transmittance and attenuation of the materials are all increased and the threshold electric field is reduced.The application scope of the material is more extensive.