Study On Modification Of Piezoelectric Ceramic Of PZT-PMN System

The precursor method is adopted to synthesis single phase PZTMN at 780℃.and the modification for PZTMN ternary system were investigated. The microstructure features, Mechanical properties and electrical properties of the ceramics were studied by using methods such as XRD,SEM and macroscopical testing.In order to enhance the Mechanical properties of PZTMN system piezoceramics, second phase oxide was introduced and (Pb0.95Sr0.05)[(Zr0.5Ti0.5)0.8(Mg1/3Nb2/3)0.2]0.98Nb0.02O3.01+ aZrO2 composites were prepared by double-precursor method. SEM indicated that the fracture of the ceramics exhibits more transgranular patterns after the enhancement oxide is added. When the doping amount of oxide are 0～2mol%, the ceramics'mechanical properties increased with increasing amount of second phase oxide. the fracture toughness KIC was enhanced from 0.83MPam1/2 to 0.98MPam1/2,andσwas enhanced from 60MPa to 76MPa. When the doping amount of oxide are more than 2mol%, the mechanical properties weaken. electrical properties were better than the matrix when the doping amount of oxide were 2mol%.In order to improve the electrical properties of PZTMN system in a further, Fe203 modification were carried out in this systerms. Fe2O3 was mixed in stoichiometric proportion to obtain Pb((Zr0.5Ti0.5)0.8(Mg1/3Nb2/3)0.2)(1-c)FecO(3-0.5c)+ 0.02ZrO2。Microstructure, sintering properties and electrical properties of the system were studied, and doping mechanism was also discussed . The result indicated that the densification can be improved by a small quantity of Fe2O3 doping, the perfect Poling condition of this system were as follows, Poling temperature was 120℃, poling electric field was 3KV/mm and poling time was 30min. This PZTMN system reached the excellent electrical properties when the doping amount of Fe203 was 2mol%, and when the content of Fe2O3 doping was>2mol%, the electrical properties were decreases.The optimized ceramic withεr=2215,tanδ=0.016, Tc=310℃,d33=520 pC/N,Kp=0.61 was obtained through Fe2O3 modification.