Applied Physics A

, Volume 91, Issue 1, pp 167–171

Phase transition and electrical properties of (K0.5Na0.5)(Nb1-xTax)O3 lead-free piezoelectric ceramics



(K0.5Na0.5)(Nb1-xTax)O3 lead-free piezoelectric ceramics have been prepared by an ordinary sintering technique. The results of X-ray diffraction reveal that Ta5+ diffuses into the K0.5Na0.5NbO3 lattices to form a solid solution with an orthorhombic perovskite structure. Because of the high melting temperature of KTaO3, the (K0.5Na0.5)(Nb1-xTax)O3 ceramics can be sintered at higher temperatures. The partial substitution of Ta5+ for the B-site ion Nb5+ decreases both paraelectric/cubic–ferroelectric/tetragonal and ferroelectric/tetragonal–ferroelectric/orthorhombic phase transition temperatures, TC and TO-T. It also induces a relaxor phase transition and weakens the ferroelectricity of the ceramics. The ceramics become ‘softened’, leading to improvements in d33, kp, kt and εr and a decease in Ec, Qm and Np. The ceramics with x=0.075–0.15 become optimum, having d33=127–151 pC/N, kp=0.43–0.44, kt=0.43–0.44, εr=541–712, tanδ=1.75–2.48% and TC=378–329 °C.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  1. 1.Department of Applied Physics and Materials Research CentreThe Hong Kong Polytechnic UniversityKowloonP.R. China
  2. 2.College of Chemistry and Materials ScienceSichuan Normal UniversityChengduP.R. China

Personalised recommendations