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J Mater Sci: Mater Electron (2013) 24:24692472 DOI 10.1007/s10854-013-1119-0
Effects of CuO doping on the structure and properties lead-free KNN-LS piezoelectric ceramics
Hua Wang Xia Zhai Jiwen Xu Changlai Yuan
Changrong Zhou
Received: 6 November 2012 / Accepted: 29 January 2013 / Published online: 7 February 2013 Springer Science+Business Media New York 2013
Abstract (0.95Na0.5K0.5NbO3-0.05LiSbO3)-x mol% CuO (KNN-LS-xCuO) lead-free piezoelectric ceramics have been fabricated by a conventional solid-state reaction route at a lower sintering temperature and the effects of CuO-dopant on structure and properties of KNN-LS ceramics have been studied. It is found that the addition of CuO signicantly improves the sinterability and properties of KNN-LS ceramics. X-ray diffraction data shows that a small amount of CuO does not change the phase structure of KNN-LS and a dense microstructure with smaller and more uniform grains is developed, probably due to liquid-phase sintering. With the increase of CuO content x, the relative density, d33, kp, tand and Qm have been improved
obviously when x \ 0.45 due to the presence of the liquid phase and the rened grains, but excessive CuO would degrade the comprehensive properties of KNN-LS-xCuO ceramics. The best specimen with a high relative density of 98.53 % was fabricated when x = 0.45 at 1,060 C, relating constants respectively are: d33 = 175pC/N, kp =
0.46, er = 551.23, tand = 1.41 %, Qm = 41.5.
1 Introduction
The market for piezoceramics ceramics is dominated by lead-based PZT materials because of the excellent electrical properties [1]. However, the use of lead-based piezoelectric materials not only brings serious environmental problems, but also leads to the unstability of the composition because of the high volatilization of lead oxide
during the sintering process. In recent years, the search for alternative piezoelectric materials has been focused on alkali niobates, modied bismuth titanates and other systems [24].
K0.5Na0.5NbO3(KNN) lead-free piezoelectric ceramics
have attracted much attention as one of the most possible substitution of lead oxides ceramics in the last few years for their good piezoelectric and electromechanical properties [57]. It was found that doping can father improve the properties of KNN piezoelectric ceramics effectively [811]. However, high quality KNN-based ceramics have generally been sintered at high temperatures ([1,100 C)
in previous studies [813]. Na2O and K2O were evaporated...