Phase transitional behavior and electrical properties of Pb(In_(1/2)Nb_(1/2))O_3-Pb(Mg_(1/3)Nb_(2/3))O_3-PbTiO_3 ternary ceramics

摘要

Relaxor based ternary (0.60 - x)Pb(In_(1/2)Nb_(1/2))O_3-0.40Pb(Mg_(1/3)Nb_(2/3))-xPbTiO_3 ((0.60 - x)PIN-0.40PMN-xPT) polycrystalline ceramics were synthesized by two-step columbite precursor method. The effects of PIN/PT content on phase structure, microstructure, density, and dielectric, piezoelectric, ferroelectric and pyroelectric properties of the ternary ceramics were systematically investigated. A morphotropic phase boundary (MPB) near x = 0.34 was identified by X-ray diffraction and further confirmed by their respective electrical properties. Piezoelectric, ferroelectric and pyroelectric properties were enhanced for compositions near the MPB. The 0.26PIN-0.40PMN-0.34PT ceramics show optimum electrical properties: piezoelectric coefficient d_(33) = 505 pC/N, planar electromechanical coupling factor k_p = 62.5 %, remnant polarization P_r = 32.1 μC/cm~2, coercive field E_c = 8.8 kV/cm, and room temperature pyroelectric coefficient p = 0.050 μC/cm~2 ℃. In addition, the rhombohedral- tetragonal phase transition temperature T_(rt) and Curie temperature T_c of the ternary ceramics were identified by the temperature dependence of dielectric and pyroelectric measurements, which are much higher than those of binary PMN-PT ceramics, indicating the expanded temperature usage range of the ternary ceramics. The results show that this ternary system is a promising candidate for electromechanical applications with high performance and wide temperature usage range.