Piezoelectric Properties of Pb(Mg1/3Nb2/3)O3 PbTiO3 ‐PbZrO3 Ceramics Modified with Certain Additives

Abstract

Effects of additives on the piezoelectric properties of Pb(Mg1/3Nb2/3)O3‐PbTiO3‐PbZrO3 ceramics in a perovskite‐type structure are described. The tetragonality of Pb(Mg1/3Nb2/3)0.375‐Ti0.375Zr0.25O3 ceramics increased with the addition of NiO, Cr2O3, or Fe2O3 but decreased with the addition of MnO2 or CoO. The dielectric and piezoelectric properties of the base composition were improved markedly through selection of additives in proper amounts. Addition of NiO yielded a high dielectric constant and planar coupling coefficient for compositions at the morphotropic transition boundary. High mechanical Q‐factors and low electrical dissipation factors were obtained by addition of MnO2. Addition of both NiO and MnO2 produced a mechanical Q‐factor of 2051 and a planar coupling coefficient of 0.553. The resonant frequency of Pb(Mg1/2Nb2/3)0.4375Ti0.4375 zr0.125O3 containing MnO2 had very low temperature and time dependence. The microstructure indicated that ceramics with a high mechanical Q‐factor had a fine, uniform grain structure. Addition of Cr2O3 retarded grain growth and addition of MnO2, NiO, CoO, or Fe2O3 promoted grain growth in the ternary system.