Structure and Piezoelectric Properties of Fe-Doped Potassium Sodium Niobate Tantalate Lead-Free Ceramics
Structure and Piezoelectric Properties of Fe-Doped Potassium Sodium Niobate Tantalate Lead-Free Ceramics
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DOI：
10.1111/j.1551-2916.2011.04390.x
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发表时间：
2011-08-01
影响因子：
3.9
通讯作者：
Jiang, Yongyuan
中科院分区：
文献类型：
--
作者：
Yang, Wenlong;Zhou, Zhongxiang;Jiang, Yongyuan
采用常规陶瓷烧结工艺制备了无铅（1-x/2）K0.5Na0.5Nb0.95Ta0.05O3-x/2Fe 2 O3（x = 0，0.2，0.4，0.6，0.8，1.0，2.0和3.0mol%）压电陶瓷。研究了掺杂铁元素对材料结构、介电性能和压电性能的影响。氧化铁（Fe 2 O3）的引入可以细化晶粒，减少微孔，提高陶瓷的致密度，从而改善陶瓷的压电性能和烧结特性。堆密度达到稳定值4.52g/cm ~ 3，约为理论值的96%。当x = 0.4mol%时，样品的压电系数d（33）和平面机电耦合系数k（P）分别达到最大值（d（33）= 130 pC/N，k（P）= 37.2%），与未掺杂样品相比，压电系数和平面机电耦合系数都有明显的提高。K+和Na+空位以及Fe离子扩散引起的电荷补偿引起了畴壁运动，这可能是改善陶瓷结构和电性能的原因。Fe_2O_3在低掺杂浓度下被认为是碱金属硅酸盐压电陶瓷的“软”添加剂。
Lead-free (1-x/2) K0.5Na0.5Nb0.95Ta0.05O3-x/2Fe(2)O(3) piezoelectric ceramics (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0, 2.0, and 3.0 mol%) have been prepared by conventional ceramic sintering process. The effects of doped iron element on the structure, dielectric, and piezoelectric properties were investigated. The introduction of ferric oxide (Fe2O3) was effective in improving the piezoelectric properties and sintering characteristics by refining grain size, reducing micropores and increasing the density of the ceramics. The bulk density reached the steady value of around 4.52 g/cm(3), about 96% of the theoretical value. The samples with x = 0.4 mol% show the maximum values of the piezoelectric coefficient (d(33) = 130 pC/N) and the planar electromechanical coupling coefficient (k(P) = 37.2%), which is significantly enhanced compared with the undoped samples. K+ and Na+ vacancies and charge compensation of the diffused Fe ions in the ceramics induce domain wall motions, which might be responsible for the improvement of structure and electrical properties. Fe2O3 was considered to be a "soft" addition for alkali niobate piezoelectric ceramics at low doping concentration.