Title :
Piezoelectric properties in (K0.5Bi0.5)TiO 3-(Na0.5Bi0.5)TiO3-BaTiO 3 lead-free ceramics
Author :
Zhang, Shujun ; Shrout, Thomas R. ; Nagata, Hajime ; Hiruma, Yuji ; Takenaka, Tadashi
Author_Institution :
Mater. Res. Inst., Pennsylvania State Univ., University Park, PA
fDate :
5/1/2007 12:00:00 AM
Abstract :
Lead-free piezoelectric ceramics with compositions around the morphotropic phase boundary (MPB) x(Na0.5Bi0.5)TiO 3-y(K0.5Bi0.5)TiO3-zBaTiO 3 [x + y + z = 1; y:z = 2:1] were synthesized using conventional, solid-state processing. Dielectric maximum temperatures of 280degC and 262degC were found for tetragonal 0.79(Na0.5Bi0.5)TiO3-0.14(K0.5 Bi0.5)TiO3-0.07BaTiO$ d3 (BNBK79) and MPB composition 0.88(Na0.5Bi0.5)TiO3-0.08(K 0.5Bi0.5)TiO3-0.04BaTiO$ d3 (BNBK88), with depolarization temperatures of 224degC and 162degC, respectively. Piezoelectric coefficients d33 were found to be 135 pC/N and 170 pC/N for BNBK79 and BNBK88, and the piezoelectric d31 was determined to be -37 pC/N and -51 pC/N, demonstrating strong anisotropy. Coercive field values were found to be 37 kV/cm and 29 kV/cm for BNBK79 and BNBK88, respectively. The remanent polarization of BNBK88 (~40 muC/cm2) was larger than that of BNBK79 (~29 muC/cm2). The piezoelectric, electromechanical, and high-field strain behaviors also were studied as a function of temperature and discussed
Keywords :
barium compounds; bismuth compounds; dielectric polarisation; piezoceramics; piezoelectricity; potassium compounds; sodium compounds; (K0.5Bi0.5)TiO3-(Na0.5 Bi0.5)TiO3-BaTiO3; (K0.5Bi0.5)TiO3-(Na0.5 Bi0.5)TiO3-BaTiO3 lead-free piezoelectric ceramics; 162 degC; 224 degC; 262 degC; 280 degC; coercive field; depolarization temperatures; dielectric maximum temperatures; electromechanical effects; high-field strain; morphotropic phase boundary; piezoelectric coefficients; piezoelectric properties; remanent polarization; Anisotropic magnetoresistance; Bismuth; Ceramics; Dielectrics; Environmentally friendly manufacturing techniques; Piezoelectric devices; Piezoelectric materials; Powders; Solid state circuits; Temperature;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
DOI :
10.1109/TUFFC.2007.336
