Structure and electrical properties of Bi_0.5Na_0.5TiO₃-Y_0.5Na_0.5TiO₃-BaTiO₃ lead-free piezoelectric ceramics

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• 作者：Dunmin Lin and K. W. Kwok
• 刊名：Journal of Materials Science: Materials in Electronics
• 出版年：2010
• 出版时间：March, 2010
• 年：2010
• 卷：21
• 期：3
• 页码：291-297
• 全文大小：3.4 MB

文摘

New (1 – x − y)Bi_0.5Na_0.5TiO₃-xY_0.5Na_0.5TiO₃-yBaTiO₃ lead-free ceramics have been prepared by a conventional ceramic fabrication technique, and their structure and electrical properties have been studied. A morphotropic phase boundary (MPB) of rhombohedral and tetragonal phases is formed at 0.04 < y < 0.10. As compared to pure Bi_0.5Na_0.5TiO₃ ceramic, the partial substitutions of Y3+ for Bi3+ and Ba2+ for (Bi_0.5Na_0.5)2+ in the A-sites of Bi_0.5Na_0.5TiO₃ lower effectively the coercive field E _c and increase the remanent polarization P _r of the ceramics. Because of low E _c, large P _r and the MPB, the ceramics with x = 0–0.02 and y = 0.06 exhibit the optimum piezoelectric properties: d ₃₃ = 155–159 pC/N and k _p = 28.8–36.7 % . The temperature dependences of dielectric properties of the ceramics show relaxor-like behaviors. The ferroelectric properties at different temperature suggest that the ceramics may contain both the polar and non-polar regions near/above T _d.