Synthesis and Dielectric Properties of (0.80 - x)Pb(Crsub1/5/sub,Nisub1/5/sub,Sbsub3/5/sub)Osub3/sub-xPbTiOsub3/sub-0.20PbZrOsub3/subFerroelectric Ceramics

摘要

Perovskite PZT variants were synthesized from stoichiometric oxide ratios of Pb, Zr, Ti, Cr, Ni and Sb. The oxide powders were mixed mechanically and calcinated, and then sintered to form the desired perovskite phase. The detailed structural and ferroelectric properties were carried out for sintered specimens. The results of X-ray diffraction showed that all the ceramics specimens have a perovskite phase. The multi-component ceramic system consists of the (0.80?- x)Pb(Cr1/5,Ni1/5,Sb3/5)O3-xPbTiO3-0.20PbZrO3 (PZT-CNS), with 0.30 ≤ x ≤ 0.42, and the ternary system near the rhombohedral/tetragonal morphotropic phase boundary(MPB) was investigated by X-ray diffraction and dielectric properties. In the present system, the MPB that coexists with the tetragonal and rhombohedral phases is a narrow composition region of x = 0.38 - 0.42. The scanning Electron Microscopy (SEM) showed an increase of the mean grain size when the sintering temperature was increased. A sintered density of 92.93% of the theoretical density was obtained for Ti = 42% after sintering at 1180°C. Ceramics sintered at 1180°C with Ti = 42% achieve excellent dielectric properties, which are as follows εr = 4262.48, and Tc = 340°C.