Phase transition characteristics and piezoelectric properties of compositionally optimized alkaline niobate based ceramics

Lead-free (Na0.52K0.48-x)(Nb0.92-xSb0.08)O-3-xLiTaO(3) ceramics with excellent dielectric and piezoelectric properties have been fabricated by ordinary sintering and their phase transition behavior, various electrical properties and temperature characteristics were investigated. The composition near x = 0.0375 exhibits a morphotropic phase boundary like behavior, and thus owns optimum electrical properties of d(33) = 395 pC/N, k(p) = 52%, epsilon(T)(33) = 2390, Q(m) = 40, N-p = 3040 Hz m and T-c = 251 degrees C. However, a strong temperature sensitivity in these compositions was observed as a result of the change of spontaneous polarization vectors or domain states, depending on the location of PPT. Compositions close to the tetragonal side exhibit much less temperature dependence, suggesting processing solutions to these obstacles. (C) 2009 Elsevier B.V. All rights reserved.