Synthesis and characterization of pseudo-ternary Pb(Fe1/2Nb1/2)O3-PbZrO3-PbTiO3 ferroelectric ceramics via a B-site oxide mixing route

摘要

Perovskite phase formation and dielectric/ferroelectric properties of the pseudo-ternary Pb(Fe1/2Nb1/2)O3-PbZrO3-PbTiO3 (PFN-PZ-PT) ferroelectric ceramics have been investigated as promising materials for multi-layer ceramic capacitors. Complete solid solution with pure perovskite phase can be formed in this system in the whole composition range studied using conventional solid-state reaction method via a B-site oxide mixing route. Crystal lattice of the ceramics obtained shrinkages with the increase of the concentration of Pb(Fe1/2Nb1/2)O3 (PFN) and expands with the increase of the content of PbZrO3 (PZ). With the increase of the concentration of PbTiO3 (PT), crystal structure of PFN-PZ-PT changes from pseudo-cubic ferroelectric phase to tetragonal one while retains the fraction of PFN as constant. A morphotropic phase boundary (MPB) forms at the composition of 42 mol% PT regardless of whatever concentration of PFN, and the content of PFN affects little on the composition of MPB. The preliminary phase diagram of the PFN-PZ-PT system is determined by X-ray diffraction (XRD) measurements combining with dielectric/ferroelectric characterization. Dielectric measurements indicate that the value of dielectric maximum (ɛ m ) and the temperature where ɛ m appears (T m ) increase with the increase of the concentration of PT. However, PFN exhibits opposite effects, i.e., ɛ m increases with the increase of the concentration of PFN accompanied by the decrease of T m .