PIEZOELECTRIC PROPERTIES OF NIOBIUM-DOPED 18PMN-41PZ-41PT CERAMICS

The effects of various amounts of excess niobium ions added to the 18P MN-41 PZ-41 PT three-component ceramics system on the crystal structur e, microstructure, polarization versus electric field, strain versus e lectric field and piezoelectric properties, have been studied. It was found that addition of niobium ions to 18PMN-41 PZ-41 PT induced a cha nge in the crystal structure from rhombohedral to tetragonal phase. Th e excessive niobium ions also formed a micro-second phase which existe d in the grain boundary, which could refine and uniform the grain. The refined and uniformed microstructure was found to increase the remane nt polarization, saturation strain, planar coupling coefficient, K(p), and mechanical quality factor, the best value of K(p) being less-than -or-equal-to 69%.