Low-Temperature Sintering and Piezoelectric Properties of ZnO-Added 0.41Pb(Ni1/3Nb2/3)O₃–0.36PbTiO₃–0.23PbZrO₃Ceramics

The structure of 0.41(PbNi 1/3 Nb 2/3 )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 1000°C, bulk density slightly decreased with the addition of ZnO but it significantly increased for the specimens sintered below 1000°C. Curie temperature ( T c ) and maximum dielectric constant increased when ZnO was added. Coercive electric field ( E c ) and mechanical quality factor ( Q m ) increased with the addition of ZnO but piezoelectric constant ( d 33 ), electromechanical coupling factor ( k p ) and dielectric constant ( ε T 3 / ε 0 ) decreased with the addition of ZnO for the specimens sintered above 1,000°C. However, for the specimens sintered below 1000°C, 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 ε T 3 / ε o = 3400 were obtained for the specimen with 3 mol% ZnO sintered at 950°C for 1 h.