Microstructure and piezoelectric properties of Li-doped Bi0.5(Na0.825K0.175)0.5TiO3 piezoelectric ceramics

Piezoelectric ceramics Bi-0.5(Na0.825K0.175)(0.5)TiO3 + x wt% Li2CO3 (abbreviated as BNKTL-x) with x ranging from 0 to 10 were synthesized by conventional solid-state reaction. XRD results reveal that the ceramics possess pure perovskite phase from x = 0 to x = 1.0. The SEM micrographs show that ceramics have a dense microstructure with a fine grain size at 1145 degrees C when x < 5.0. The measurements of dielectric and piezoelectric properties indicate that the optimum piezoelectric properties constant d(33) = 174 pC/N at x = 0.5 and planar electromechanical coupling factor k(P) = 29.7% at x = 0.75 are observed. The depolarization temperature T-d of BNKTL-1.0 ceramics is above 170 degrees C. It is apparent that the ceramics can be employed in practical applications. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim