Microstructure and piezoelectric properties of Li‐doped Bi 0.5 (Na 0.825 K 0.175 ) 0.5 TiO 3 piezoelectric ceramics

Piezoelectric ceramics Bi 0.5 (Na 0.825 K 0.175 ) 0.5 TiO 3 + x wt% Li 2 CO 3 (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 °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 °C. It is apparent that the ceramics can be employed in practical applications. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)