Structure, piezoelectric and ferroelectric properties of Li- and Sb-modified K0.5Na0.5NbO3 lead-free ceramics

Lin, D., Kwok, K.W., Lam, K.H. and Chan, H.L.W. (2007) Structure, piezoelectric and ferroelectric properties of Li- and Sb-modified K0.5Na0.5NbO3 lead-free ceramics. Journal of Physics D: Applied Physics, 40(11), pp. 3500-3505. (doi: 10.1088/0022-3727/40/11/036)

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Abstract

Lead-free ceramics (K0.5Na0.5)1−xLix(Nb1−ySby)O3 have been prepared by an ordinary sintering technique. Li+ and Sb5+ diffuse into the K0.5Na0.5NbO3 lattices to form a solid solution with the perovskite structure. The substitution of Li+ increases the Curie temperature Tc and shifts the ferroelectric tetragonal–ferroelectric orthorhombic phase transition (TO–T) to low temperatures. On the other hand, the substitution of Sb5+ decreases Tc and has a minor effect on TO–T. The coexistence of the orthorhombic and tetragonal phases at x = 0.06 and y = 0.06 near room temperature and the strong covalence of Sb lead to significant improvements in the piezoelectric properties. For the (K0.5Na0.5)0.94Li0.06(Na0.94Sb0.06)O3 ceramic, piezoelectric constant d33 = 212 pC N−1, planar and thickness electromechanical coupling factors kP = 46% and kt = 47% and Tc = 358 °C. The donor-type doping of BaCO3, SrCO3 or Bi2O3 leads to further enhancements of the piezoelectric and ferroelectric properties.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Lam, Dr Koko
Authors: Lin, D., Kwok, K.W., Lam, K.H., and Chan, H.L.W.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Journal of Physics D: Applied Physics
Publisher:IOP Publishing
ISSN:0022-3727
ISSN (Online):1361-6463
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