A Study On Preparation Of PLZT Nano-ceramics And Modification With Doping

[Pb_1-x/100La_x/100(Zr_y/100Ti_z/100)_1-x/400O₃] (abbreviated as PLZT(x/y/z)) is an excellent transparent ferroelectric ceramics. It presents excellent electrooptical effect and photostrictive effect under an electric field. So, PLZT has a variety of applications including electrooptical switching, sensor and driving motors,etc. PLZT Powders preparation is very important to obtain the transparent electrooptical ceramics. Large grain size and agglomeration problem in the powder processing confine the development of PLZT. So the modification of nanopowder preparation could expand the range of PLZT application.In the study PLZT nanometer crystalline ceramics were prepared by improving coprecipitaion method and hydrothermal synthesis process.We obtained four kinds of metal ion coprecipitaion and retain the equivalent stoichiometric proportion when H₂O₂ was used as activator, Polyethylene glycol, ethanol and H₂O were used as dispersant agent and pH=9.6. The nanaocrystalline ceramics powders were obtained under coprecipitaion precursor were calcining at 710℃. The ceramics were investigated by XRD, TEM .The results show that the ceramics powders with cubic perovskite structure in size of 92 nm have been obtained. After presintering with fusing agent and sintering under pressureless at 1100℃ the compact nano-ceramics are obtained. By means of positron annihilation technology the microstructure and deficiency of PLZT with different content of La³⁺ doped were investigated. It is found that cation vacancies and lattice deformations in PLZT increase with the increasing of the concentration of La³⁺ , cation vacancies diminish and concentration increment decrease when La³⁺≥9%. Upon investigating the dielectric property by Precision Impendance Analyzers (PIA) at the room temperature and 1 KHz.The results show that the relative dielectric constant of PLZT(9/65/35) is quite high:ε_r=4997.Hydrothermal synthesis of the PLZT by orthogonal test,we obtained optimal preparation condition: concentration of KOH is 4 mol·L^-1,T=200℃, excess lead =10%,time is 10 h. The nanosized powders were analyzed by XRD and TEM, the results show that PLZT nonapowders with tetragonal-phase in size of 80 nm are obtained. Upon...