Eco-friendly (Na, K) Nb03 (NKN)-based piezoelectric ceramic materials were fabricated by conventional ceramic method for shear mode piezoelectric energy harvesting application. NKN-LiTaO3 (LT) based compositions were adopted for the high d15xg15 which is proportional to harvested energy density. The composition 0.935(Na0.535K0.485) NbO3-0.065LiTaO3 was found to be lie on the boundary of tetragonal and orthorhombic phases. With reducing Ta content, the dielectric constant decreased gradually while maintaining high d15, which resulted in increased d15xg15, The composition 0.935(Nao0.535K0.485)) NbO-0.065Li (Nb0.990Ta0.0010) O3 was found to possess excellent piezoelectric and electromechanical properties (d15sxg15 =29 pm2/N, d13 417pC/N, k15= 0.55), and high curie temperature (T 455t).

In this study, thickness shear mode piezoelectric devices for AE sensor with excellent displacement and sensitivity characteristics were simulated using ATILA FEM program, and then fabricated. Displacement and electro mechanical coupling factors of the piezoelectric devices were investigated. The simulation results showed that excellent displacement and electromechanical coupling factor was obtained when the ratio of Length/Thickness was 1. The piezoelectric device of L/T=1 exhibited the optimum values of fr=150 kHz, displacement= 6.23×10(-8)[m], k15= 0.598. The results show that the thickness shear mode piezoelectric device is a promising candidate for the application of AE sensor piezoelectric device.