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Piezoelectric Properties of K 0.47 Na 0.47 Li 0.06 NbO 3 –NaSbO 3 Lead‐Free Ceramics for Ultrasonic Transducer Applications
Author(s) -
Lin Dunmin,
Kwok Kin Wing
Publication year - 2011
Publication title -
international journal of applied ceramic technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 57
eISSN - 1744-7402
pISSN - 1546-542X
DOI - 10.1111/j.1744-7402.2010.02500.x
Subject(s) - materials science , piezoelectricity , tetragonal crystal system , ceramic , ferroelectricity , orthorhombic crystal system , dielectric , electromechanical coupling coefficient , phase (matter) , piezoelectric coefficient , perovskite (structure) , composite material , crystal structure , optoelectronics , crystallography , chemistry , organic chemistry
Lead‐free piezoelectric ceramics (1− x )K 0.47 Na 0.47 Li 0.06 NbO 3 – x NaSbO 3 have been prepared by a conventional solid‐state sintering technique. Our results reveal that NaSbO 3 diffuses into the K 0.5 Na 0.5 NbO 3 lattices to form a solid solution with a perovskite structure. After the addition of NaSbO 3 , both the paraelectric cubic–ferroelectric tetragonal and ferroelectric tetragonal–ferroelectric orthorhombic phase transition temperatures decrease. Coexistence of the orthorhombic and tetragonal phases is formed in the ceramics with x =0.04–0.10 at room temperature. In addition to the increase of the Na + /K + ratio and the strong covalence of Sb, the piezoelectricity of the ceramics is improved. For the ceramic with x =0.09, the piezoelectric properties become optimum, giving a piezoelectric coefficient d 33 of 305 pC/N, and electromechanical coupling factors k p and k t of 0.51. The ceramics also exhibit excellent performance in transducer applications, indicating that the ceramics are ready for replacing lead‐containing ceramics in practical applications.