织构化铌酸钾钠无铅压电陶瓷的性能研究

Properties of Textured Potassium-sodium Niobate Lead-free Piezoelectric Ceramic

以固相法合成的K0.5Na0.5NbO3(KNN)粉体基料,熔盐法合成的片状Sr2Bi4Ti5O18晶粒为模板,采用水系流延法制备织构化KNN无铅压电陶瓷,研究了烧结温度对材料性能的影响。发现烧结温度对陶瓷的体积密度、线收缩率、织构度和压电性能均有重要影响。随着烧结温度的升高,压电性能逐渐提高,1120℃时达到最大值。其中平行于流延方向的压电常数d33达到113pC/N,平面机电耦合系数kp为39.4%,介电常数εT33/ε0为486;而垂直于流延方向d33只有82pC/N,kp为35.5%,介电常数εT33/ε0为456,显示出明显的各向异性。

In this paper, K_0.5Na_0.5NbO_3 （KNN） synthesized by solid state reaction as base materials, flake Sr_2Bi_4Ti_5O_18 grain prepared by molten salt synthesis method as template, the KNN textured lead-free piezoelectric ceramic was prepared by aqueous tape-casting technique, and the effect of sintering temperature on the performance was studied. The results showed that the sintering temperature has very important inlfuence on the linear shrinkage, bulk density, texturing and piezoelectric properties. With the increase of sintering temperature, the performance increases and reaches maximum at 1120℃ and then decreases. In the parallel tape-casting direction, the piezoelectric constant d_33 reaches 113 pC/N, the planar electromechanical coupling coefifcient k_P is 39.4%, the dielectric constant ε^T_33/ε_0 is 486; and at the perpendicular direction, the d_33is only 82 pC/N, the kP is 35.5%, and the ε^T_33/ε_0 is 456, showing obvious anisotropy.