Simultaneous preparation and densification of lead magnesium niobate-based ferroelectrics

Ferroelectric lead titanate-doped lead magnesium niobate ceramics have been prepared and densified simultaneously by a new reaction sintering process. At low temperatures, the pyrochlore phase is firstly formed, which induces the expansion of the specimens. When the perovskite phase begins to produce at elevated temperatures, the specimens rapidly shrink, indicating the occurrence of reaction sintering. After sintering at 850 degreesC. monophasic Pb(Mg1/3Nb2/3)O-3-PbTiO3 solid solutions with high density are obtained. With an increase in the doping amount of PbTiO3, the maximum dielectric permittivity and the Curie temperature increase, however, the relaxer characteristics of Pb(Mg1/3Nb2/3)O-3 become weakened. With the addition of 15 mol% PbTiO3, the maximum dielectric permittivity is over 25000 at 1 kHz. It is concluded that monophasic and densified Pb(Mg1/3Nb2/3)O-3-PbTiO3 with high dielectric permittivity are successfully prepared by the newly developed reaction sintering process.