Effect of MnO2 on the piezoelectric properties of (1-x)(Na0.5K0.5)NbO3-xBaTiO3 ceramics

(Na0.5K0.5)NbO3 (NKN) and BaTiO3 (BT) ceramics form a homogeneous solid Solution. The relative density of the (1 - x)NKN-xBT solid solutions significantly decreased when x <= 0.07. Although the relative density of the 0.95NKN-0.05BT ceramic was very low, it had a high d(33) value of 134pC/N. MnO2 was added to improve the piezoelectric properties of the 0.95NKN-0.05BT ceramics by enhancing their sinterability. The addition of MnO2 increased the density of the specimens, as well as improving the piezoelectric properties. The 0.9 mol % MnO2 added 0.95NKN-0.05BT ceramics showed the good piezoelectric properties of k(p) = 0.31, d(33) = 194 pC/N and epsilon(T)(3)/epsilon(0) = 800.