Synthesis and piezoelectric and ferroelectric properties of (Na0.5Bi0.5)1-xBaxTiO3 ceramics

(Na0.5Bi0.5)(1-x)BaxTiO3 powders were synthesized by a citrate method, and the piezoelectric and ferroelectric properties of the ceramics were investigated. The results indicate that the citrate method is an advantageous alternative route to the conventional method in producing (Na0.5Bi0.5)(1-x)BaxTiO3 ceramics. Homogeneous and fine powders with a pure perovskite structure were derived from precursor solutions with a mole ratio of citric acid to total metal cation content (C/M) of 1.25 by calcining at 600degreesC for 1 h. The ceramics made by the citrate method exhibit superior piezoelectric properties near the rhombohedral-tetragonal morphotropic phase boundary. The piezoelectric constant (d(33)) and electromechanical coupling factor (k(p)) attain maximum values of d(33) = 180 pC N-1 and k(p) = 0.28 at x = 0.06, corresponding to a relatively large remanent polarization of P-r = 37.1 muC cm(-2) and a relatively low coercive field of E-c = 42.7 kV cm(-1). (C) 2004 Elsevier B.V. All rights reserved.