一种改性铌酸盐系无铅压电陶瓷的合成与特性研究

Synthesis and properties of doped potassium-sodium niobate lead-free piezoelectric ceramics

K_(0.5)Na_(0.5)NbO_3(KNN)系铌酸盐是一类可能替代铅基压电陶瓷的无铅压电陶瓷。利用Ta和Sb掺杂或者取代KNN中的相关离子,在陶瓷的准同型相界(MPB)处显现出高的压电和介电性能.利用传统技术制作出一种新的致密度较高的无铅压电陶瓷(1 -x(K_(0.5)Na_(0.5))(Nb_(0.96)Sb_(0.04))O_(3-x)LiTaO_3(简记为KNNS-LT)。所有的组分在MPB处都存在纯的钙钛矿结构,主要压电性能在MPB处达极大值,其机电耦合系数k_p为40%,压电常数d_(33)为225pC/N,居里温度T_c为355℃。

Potassium-sodium niobate ceramics,K0.5Na0.5 NbO3 （KNN）,are considered to be excellent candidates of lead-free piezoelectric ceramics. The systems of KNN piezoelectric ceramics adulterated or replaced by tantalum et al show relatively high piezoelectric and dielectric properties at the composition near the morphotropic phase boundary （MPB）. In this paper, （ 1 - x） （K0. 5 Na0.5 ） （N b0.96 Sb0.04 ） O3-x LiTaO3 （KNNS-LT） piezoelectric ceramics have been fabricated by ordinary techniques. Near the MPB the ceramics of all compositions show pure perovskite structures and possess peak piezoelectric values. The ceramics with x=0.04 show the planar electromechanical coupling factor kp of 40%, the piezoelectric constant d33 of 225pC/N,and the Curie temperature of 355℃, which can be comparable to those of the commercial lead zinconate titanate ceramics.