Dielectric and piezoelectric properties of MnO₂-doped K_0.5Na_0.5Nb_0.92Sb_0.08O₃ lead-free ceramics

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• 作者：Dunmin Lin ; Qiaoji Zheng ; K. W. Kwok ; Chenggang Xu and Chun Yang
• 刊名：Journal of Materials Science: Materials in Electronics
• 出版年：2010
• 出版时间：July, 2010
• 年：2010
• 卷：21
• 期：7
• 页码：649-655
• 全文大小：907.4 KB

文摘

Lead-free MnO₂-doped K_0.5Na_0.5Nb_0.92Sb_0.08O₃ ceramics have been fabricated by a conventional ceramic technique and their dielectric and piezoelectric properties have been studied. Our results show that a small amount of MnO₂ (0.5–1.0 mol % ) is enough to improve the densification of the ceramics and decrease the sintering temperature of the ceramics. The co-effects of MnO₂ doping and Sb-substitution lead to significant improvements in the ferroelectric and piezoelectric properties. The K_0.5Na_0.5Nb_0.92Sb_0.08O₃ ceramic with 0.5 mol % MnO₂ doping possesses optimum propeties: d ₃₃ = 187 pC/N, k _P = 47.2 % , ε _r = 980, tanδ = 2.71 % and T _c = 287 ¡ãC. Due to high tetragonal-orthorhombic phase transition temperature (T _O-T ~ 150 ¡ãC), the K_0.5Na_0.5Nb_0.92Sb_0.08O₃ ceramic with 0.5 mol % MnO₂ doping exhibits a good thermal stability of piezoelectric properties.