锰掺杂对(K_(0.5)Na_(0.5))NbO_3-LiNbO_3压电陶瓷结构和性能的影响

采用传统陶瓷制备工艺制备了(K_(0.5)Na_(0.5))NbO_3-LiNbO_3-xMnO_2压电陶瓷,分析了陶瓷样品的微观组织结构.实验结果表明,随MnO_2掺杂量的增多,陶瓷由四方相转变为正交相,晶粒的均匀性下降并生成K_3LiNb_6O_(17)相.研究了MnO_2不同掺杂量对陶瓷压电性能的影响.结果表明,随锰掺杂量的增加,材料逐渐变"硬",机电耦合系数k_p和压电常数d_(33)逐渐减小,同时Q_m逐渐增大;当MnO_2含量为0.8%(质量分数)时,陶瓷的机械品质因数达到最大,此时陶瓷的压电性能为:k_p=0.34,k_t=0.43,d_(33)=110pC/N,Q_m=401.3.

Effects of Doping MnO_2 on Microstructure and Piezoelectric Properties of (K_(0.5) Na_(0.5)) NbO_3-LiNbO_3 Ceramics

Piezoelectric ceramics (K_(0.5) Na_(0.5))NbO_3-LiNbO_3-xMnO_2 are prepared by traditional ceramic process. The phase structure is analyzed. The results show that the phase structure changes from tetragonal phase to orthogonal phase with the content of MnO_2 increasing. The new phase K_3LiNb_6O_(17) is formed. The effect of MnO_2 doping on the piezoelectric properties is investigated. When the content of MnO_2 increases, the mechanical coupling factor k_p and piezoelectric constant d_(33) decrease, while the mechanical quality factor Q_m increases. When the content of MnO_2 is 0.8%, the piezoelectric properties of the ceramic are as follows: k_p=0.34, k_t=0.43, d_(33) =110pC/N, Q_m=401.3, respectively.