Low-temperature sintering and piezoelectric properties of ZnO-added 0.41Pb(Ni1/3 Nb2/3)O3-0.36PbTiO3-0.23PbZrO3 ceramics

The structure of 0.41(PbNi1/3Nb2/3)O-3-0.36PbTiO(3)-0.23PbZrO(3) (0.41PNN-0.36PT-0.23PZ) ceramics changed from pseudocubic to tetragonal when ZnO was added. For the specimens sintered above 1000degreesC, bulk density slightly decreased with the addition of ZnO but it significantly increased for the specimens sintered below 1000degreesC. Curie temperature (T,) and maximum dielectric constant increased when ZnO was added. Coercive electric field (E-c) and mechanical quality factor (Q) increased with the addition of ZnO but piezoelectric constant (d(33)), electromechanical coupling factor (k(p)) and dielectric constant (epsilon(3)(T)/epsilon(0)) decreased with the addition of ZnO for the specimens sintered above 1,000degreesC. However, for the specimens sintered below 1000degreesC, the addition of ZnO significantly improved the piezoelectric and dielectric constants, which could be due to the improvement of bulk density. The good dielectric and piezoelectric properties of d(33) = 525 (pC/N), k(p) = 0.53 and epsilon(3)(T)/epsilon(0) = 3400 were obtained for the specimen with 3 mol% ZnO sintered at 950degreesC for 1h.