In this study, lead-free (K0.5Na0.5+X)(Nb0.96Sb0.04)O3+0.2mol%La2O3+1.2mol% K4CuNb8O23 (X= 0∼0.025) ceramics were fabricated by normal sintering method at 1060℃ for 5 h. Microstructures, piezoelectric and dielectric properties of specimens were investigated with special emphasis in the influence of Na excess addition. The grain size of specimen was slightly decreased with increasing Na content. In the 2 [mol%] Na excess addition of NKNS ceramics, density, electromechanical coupling factor, piezoelectric constant and electromechancal quality factor of specimen were found to reach the optimum values of 4.25 [g/cm3], 0.4357, 154.43 [pC/N] and 580, respectively.
