Ryu Jungho, Choi Jong-Jin, Hahn Byung-Dong, Park Dong-Soo, Yoon Woon-Ha, Kim Kun-Young
Center for Future Technology, Korea Institute of Materials Science, Changwon, Kyungnam, Korea.
IEEE Trans Ultrason Ferroelectr Freq Control. 2007 Dec;54(12):2510-5. doi: 10.1109/TUFFC.2007.569.
This paper investigates the effect of K(1.94)Zn(1.06)Ta(5.19)O(15) (KZT) addition on the sintering behavior and piezoelectric properties in lead free piezoelectric ceramics of (K(0.5)Na(0.5))NbO(3) (KNN). The apparent density of sintered KNN ceramics was increased with KZT addition, and a relative density of above 96.3% was obtained with the doping of over 0.5 mol% KZT. The maximum dielectric and piezoelectric properties of epsilon(T)(3)/epsilon(0) = 590, d(33) = 126 pC/N, k(p) = 0.42, and P(r) = 18 microC/cm(2) were obtained from 0.5 mol% KZT-doped KNN ceramics. A small amount of KZT (about 0.5 mol%) was effective for improving the sintering behavior and piezoelectric properties, but KZT addition exceeding 1.0 mol% was effective only for densification. A small amount of KZT was effective for densification of KNN ceramics by promoting K(5.75)Nb(10.8)O(30) liquid phase formation. However, even though KNN with 1.0 to approximately -2.0 mol% KZT had a relative density of >98.5%, the piezoelectric properties were inferior to those of 0.5 mol% KZT-doped KNN, presumably due to the smaller grain size and excess liquid phase of the KNN ceramics doped with higher amounts of KZT. It is believed that a small amount of KZT could be one of the suitable sintering aids to obtain highly dense KNN based piezoelectric.
本文研究了添加K(1.94)Zn(1.06)Ta(5.19)O(15)（KZT）对（K(0.5)Na(0.5)）NbO(3)（KNN）无铅压电陶瓷烧结行为和压电性能的影响。添加KZT后，烧结KNN陶瓷的表观密度增加，当KZT掺杂量超过0.5 mol%时，相对密度可达到96.3%以上。0.5 mol% KZT掺杂的KNN陶瓷具有最大的介电和压电性能，分别为ε(T)(3)/ε(0)=590、d(33)=126 pC/N、k(p)=0.42和P(r)=18 μC/cm(2)。少量的KZT（约0.5 mol%）有助于改善烧结行为和压电性能，但KZT添加量超过1.0 mol%仅对致密化有效。少量的KZT通过促进K(5.75)Nb(10.8)O(30)液相形成，对KNN陶瓷的致密化有效。然而，即使KZT含量为1.0至约-2.0 mol%的KNN相对密度>98.5%，其压电性能仍低于0.5 mol% KZT掺杂的KNN，这可能是由于KZT掺杂量较高时KNN陶瓷的晶粒尺寸较小且存在过量液相。据信，少量的KZT可能是获得高密度KNN基压电材料的合适烧结助剂之一。
