Articles written in Bulletin of Materials Science
Volume 36 Issue 2 April 2013 pp 265-270
To improve the piezoelectric properties of Bi0.5Na0.5TiO3-based ceramics, a new perovskite-type leadfree piezoelectric (1 – 𝑥 – 𝑦)Bi0.5Na0.5TiO3−𝑥Bi0.5K0.5TiO3−𝑦BiMnO3 system has been fabricated by a conventional solid–state reaction method and their microstructure, dielectric and piezoelectric properties have been investigated. The results of X-ray diffraction (XRD) analysis reveal that the addition of small amounts of BiMnO3 did not cause a remarkable change in crystal structure, but resulted in an evident evolution inmicrostructure. An obvious secondary phase was observed in samples with high Bi0.5K0.5TiO3 content. It is found from dielectric constant curves that low-temperature hump disappeared with increasing y and it appeared again with increasing x. The piezoelectric properties significantly increase with increasing Bi0.5K0.5TiO3 and BiMnO3 content. The piezoelectric constant and electromechanical coupling factor attain maximum values of 𝑑33 = 182 pC/N at 𝑥 = 0.21(𝑦 = 0.01) and 𝑘p = 0.333 at 𝑥 = 0.18 (𝑦 = 0.01), respectively.
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