Effects of CuO and ZnO additives on sintering temperature and piezoelectric properties of 0.41Pb(Ni1/3Nb2/3)O3-0.36PbTiO3-0.23PbZrO3 ceramics

ZnO-added 0.41PNN-0.36PT-0.23PZ ceramics cannot be sintered below 950degreesC. However, when CuO is added, the liquid phase forms and specimens can be sintered even at 850degreesC. The dielectric constant (epsilon(3)(T)/epsilon(0)), piezoelectric constant (d(33)) and electromechanical coupling factor (k(p)) increase with the addition of CuO and this is due to the enhancement of the density of the specimens. When CuO is added to 0.41PNN-0.36PT-0.23PZ ceramics, improvements of density, epsilon(3)(T)/epsilon(0), d(33) and k(p) are also observed. However, the d(33) and k(p) values of the CuO-added 6.41PNN-0.36PT-0.23PZ ceramics are less than those of the CuO- and ZnO-added specimens. Therefore, ZnO is effective in improving the piezoelectric properties of 0.41PNN-0.36PT-0.23PZ ceramics. Good dielectric and piezoelectric properties of d(33) = 575(pC/N), k(p) = 0.55 and epsilon(3)(T)/epsilon(0) = 3900 are obtained for 0.41PNN-0.36PT-0.23PZ+3.0mol% ZnO with 1 mol% CuO sintered at 900degreesC for 2 h.