Research on preparation and properties of fluorine substituted PMN-PT ceramics

The fluorine substituted PMN-PT ceramics with pure perovskite phase were prepared by semichemical method, and the fluorine came from the raw material PbF₂. The density of these ceramics increased with the increase of fluorine contents. For the pure PMN-PT ceramic, the grain size is larger, approximately 10μm, and the peaks of dielectric constants and dielectric loss are sharper, and the peak value of dielectric constant is abnormally high, about 45000, and the P-E hysteresis loop is more rectangular, and the remnant polarization is about 30μC/cm², and the piezoelectric constant is about 420 pC/N. However, in the samples contained fluorine, the sample with 2% mole fraction of F has better microstructure and dielectric and piezoelectric properties. The grains size is about 2-3μm, and the peak value of dielectric constants is about 30000, and the remnant polarization is about 30μC/cm², and the piezoelectric constant is about 380 pC/N.