Phase transition and electrical properties of (K0.5Na0.5)(Nb1-xTax)O3lead-free piezoelectric ceramics

Dunmin Lin, Kin Wing Kwok, H. L.W. Chan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

80 Citations (Scopus)


(K0.5Na0.5)(Nb1-xTax)O3lead-free piezoelectric ceramics have been prepared by an ordinary sintering technique. The results of X-ray diffraction reveal that Ta5+diffuses into the K0.5Na0.5NbO3lattices to form a solid solution with an orthorhombic perovskite structure. Because of the high melting temperature of KTaO3, the (K0.5Na0.5)(Nb1-xTax)O3ceramics 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, TCand 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, ktand εrand a decease in Ec, Qmand 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.
Original languageEnglish
Pages (from-to)167-171
Number of pages5
JournalApplied Physics A: Materials Science and Processing
Issue number1
Publication statusPublished - 1 Apr 2008

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)


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