PVDF/PZNZT压电复合材料的结构与性能

为了扩展压电复合材料的应用领域,首先,通过固相合成法制备了0-3型聚偏氟乙烯(PVDF)/Pb(Zn_1/3Nb_2/3)_0.05Zr_0.47Ti_0.48O₃ (PZNZT)压电复合材料;然后,研究了PVDF含量对PVDF/PZNZT复合材料物相、显微结构及性能的影响。结果表明:PZNZT陶瓷粉料与PVDF粉料混合后,其平均粒度接近于纯PVDF粉料的。于220℃下烧结后, PVDF/PZNZT复合材料在XRD谱图中主要显现出PZNZT钙钛矿结构的衍射峰。当PVDF含量较低时, PZNZT陶瓷晶粒间的结合较松散;随着PVDF含量的增加,陶瓷晶粒几乎都被PVDF相包围。因显微结构不同,不同PVDF含量的PVDF/PZNZT复合材料在极化电场中呈现出不同的串、并联电路。极化后, 5wt% PVDF/PZNZT复合材料的电性能最佳,其介电常数为116、介电损耗tan δ为0.04、压电常数为48 pC/N且机电耦合系数为0.28。随PVDF含量的增加, PVDF/PZNZT复合材料的居里温度降低,维氏硬度有所增加,但仍小于纯PZNZT压电陶瓷的硬度。所得结论显示PVDF/PZNZT压电复合材料的性能可以满足水声、电声及超声换能器等的要求。 

Structures and properties of PVDF/PZNZT piezoelectric composites

In order to extend the application area of piezoelectric composites, 0-3 type polyvinylidene fluoride (PVDF)/Pb(Zn_1/3Nb_2/3)_0.05Zr_0.47Ti_0.48O₃ (PZNZT) piezoelectric composites were prepared using solid reaction process firstly. Then, the effects of PVDF content on the phase, microstructures and properties of PVDF/PZNZT composites were investigated. The results show that the average particle size of PZNZT ceramic powders after mixing with PVDF powders is close to that of pure PVDF powders. After sintering under 220℃, the diffraction peaks of PZNZT perovskite structure present in the XRD patterns of PVDF/PZNZT composites mainly. When PVDF content is lower, the combinations between PZNZT ceramic grains are relatively loose; with PVDF content increasing, the ceramic grains are almost surrounded by PVDF phase. The PVDF/PZNZT composites with different PVDF contents present different series and parallel circuits in polarization electric field for the different microstructures. After polarization, the electric-properties of 5wt% PVDF/PZNZT composite are the best, the dielectric constant is 116, dielectric loss tan δ is 0.04, piezoelectric constant is 48 pC/N and electromechanical coupling coefficient is 0.28. With PVDF content increasing, the Curie temperature of PVDF/PZNZT composite decreases, and the Vickers hardness increases, but still smaller than the hardness of pure PZNZT piezoelectric ceramic. The conclusions obtained show that the properties of PVDF/PZNZT piezoelectric composites can meet the requirements of underwater acoustic, electroacoustic and ultrasonic transducers et al.