(1-x)Na_(0.5)Bi_(0.5)TiO_3-xNaNbO_3系无铅压电陶瓷的机电性能

ELECTROMECHANICAL PROPERTIES OF LEAD-FREE PIEZOELECTRIC CERAMICS FOR (1-x)Na_(0.5)Bi_(0.5)TiO_(3)-xNaNbO_(3) SYSTEM

采用传统陶瓷的制备方法,制备了(1-x)Na0.5Bi0.5TiO3-xNaNbO3(x=0～0.08)压电陶瓷。X射线衍射分析表明:所研究的组成 均能够形成纯钙钛矿(ABO3)型固溶体。不同频率下陶瓷材料的介电常数温度曲线显示该体系材料具有典型的弛豫铁电体特征,且随着x 的增加,其弛豫性特征愈明显。室温下陶瓷材料的饱和电滞回线表明:所研究组成均为铁电体,材料的剩余极化强度Pr在x=0.02时具有最 大值。检测了不同组成陶瓷的压电性能,发现材料的压电常数d33和平面机电耦合系数Kp随着x值的增加先增加后降低,在x=0.02时,陶瓷 的d33=88pC/N,Kp=0.1792,为所研究组成中的最大值,材料的介电常数εT33/ε0和介电损耗tanδ则随x值的增加而增加。

Lead-free piezoelectric ceramics of (1-x) Na0.5Bi0.5TiO3-x NaNbO3 (x=0-0.08) were fabricated by conventional ceramic preparation technique. X-ray diffraction patterns indicate that all ceramics studied can form pure perovskite structure. The dielectric constants as a function of temperature at different frequencies show that these ceramics are typical relaxor ferroelectric. The relaxor characteristic becomes more obvious with the increasing of the content of NaNbO3. Saturated polarization to electric field (P-E) hysteresis loops show that all ceramics are ferroelectrics at room temperature. When x=0.02, the remanent polarization Pr is at the maximum value for the ceramics, which corresponds to the maximum piezoelectric properties. It is found that the piezoelectric constant d33 and planar electromechanical coupling factor Kp increase first and then decrease with the increase of x value. The best d33 is 88 pC/N and Kp is 0.1792. The dielectric constant Ε33T/Ε0 and dielectric loss tan δ increase with increasing of x value.