In this paper, in order to develop excellent Pb-free composition ceramics for ultrasonic sensor. The SnO2-doped (Na0.525K0.443Li0.037)(Nb0.883Sb0.08Ta0.037)O3)(abbreviated as NKL-NST) ceramics have been synthesized using the ordinary solid state reaction method. The effect of SnO2-doping on their dielectric and piezoelectric properties was investigated. The ceramics doped with 0 wt% SnO2 have the optimum values of piezoelectric constant(d33), piezoelectric figure of merit(d33·g33), planar piezoelectric coupling coefficient(kp) and density : d33= 195[pC/N], d33·g33=5.62 pm2/N.kp= 0.40, density= 4.436[g/cm3]. suitable for duplex ultrasonic sensor application.
