Dielectric properties of Pb(Mg1/3Nb2/3)O3-PbTiO3 ferroelectric ceramics near the morphotropic phase boundary

The 0.67Pb(Mg1/3Nb2/3)O-3-0.33PbTiO(3) ferroelectric ceramics were synthesized by the columbite precursor method. The phase compositions, microstructure and dielectric properties of the samples sintered under two different kinds of PbO-rich protection atmosphere were investigated. Although X-ray diffraction results indicate that no trace of pyrochlore is present in sintered samples of both buried in and surrounded by PbZrO3 powder, the dielectric properties of samples buried in PbZrO3 powder are significantly better than the samples surrounded by PbZrO3 powder. The second phase with low dielectric constant through PbO absorption from the PbO-rich protection atmosphere deceases the dielectric constant of the sintered ceramics. It is necessary to suppress the PbO evaporation as well as PbO absorption in order to attain excellent dielectric properties.