[(Na_xK_((1–x)))_(0.985)Bi_(0.015)](Nb_(0.97)Ti_(0.03))O_3陶瓷的压电与介电性能研究

Piezoelectric and Dielectric Properties of [(Na_xK_((1-x)))_(0.985)Bi_(0.015)](Nb_(0.97)Ti_(0.03))O_3 Ceramics

采用固相法制备了[(NaxK(1–x))0.985Bi0.015](Nb0.97Ti0.03)O3(x=0.40～0.65)无铅压电陶瓷,研究了样品的物相结构、显微形貌、压电以及介电性能随x的变化规律。结果表明:所有样品都具有钙钛矿结构并且居里温度TC在340～365℃范围内;当x=0.40和x=0.65时,样品为四方相结构;在0.45≤x≤0.63范围内,形成了典型的PPT(polymorphic phase transition),样品表现出较高的压电活性。当x=0.60时,样品的压电性能最佳(d33=253 pC/N,kp=0.43,TC=359℃)。

[（NaxK（1-x））0.985Bi0.015]（Nb0.97Ti0.03）O3 （x=0.40-0.65） lead-free piezoelectric ceramics were synthesized by solid-state reaction method. The influences of different x value on the phase structure, microstructure, piezoelectric and dielectric properties of samples were studied in detail. The results indicate that all samples possess pure perovskite structure and the Curie temperature of all samples are in the temperature range of 340-365℃. The ceramic sample with x=0.40 is in the tetragonal symmetry at room temperature and with the increase of x content, the phase structure of samples change gradually from pure tetragonal phase to coexistence of tetragonal and orthorhombic phase, while the ceramic sample with x=0.65 has tetragonal phase. The polymorphic phase transition （PPT） from orthorhombic to tetragonal symmetry near room temperature locates in the composition of 0.45≤x≤0.63 in which the ceramic samples possess relatively high piezoelectric activity. The ceramic sample （x=0.60） with optimum piezoelectric properties （d33=253 pC/N, kv=0.43, Tc=359℃） is a promising lead-free piezoelectric material.