【作者】 游达；

【导师】 张联盟； 董玉琳；

【作者基本信息】 武汉理工大学 ， 材料学， 2003， 硕士

【摘要】 压电复合材料一般是由压电陶瓷和聚合物基体按照一定的连接方式，一定比例和一定的空间几何分布复合而成。由于这种复合材料兼有组成复合材料各组分的性能，克服了陶瓷和聚合物两者的不足，具有强压电性、脆性低、密度和介电系数低、易制得大面积薄片以及复杂形状制品，制造工艺简单等优点。论文首先利用Banno Unit Cell模型，计算了PZT／PVDF压电复合材料的组成、结构、与其压电和介电等性能之间的关系；针对压电复合材料存在的均匀分散性差的缺点，选用水热法制备的粒度均匀的PZT陶瓷粉末，并采用溶液混和法与聚合物PVDF进行分散复合，重点研究了不同工艺条件下陶瓷的均匀分散性及其与材料微观结构之间的关系。制备了少量PAn添加的PVDF／PZT复合材料，对其微观结构就压电和介电性能作了较为系统的分析。最后依据性能测试结果对计算模型进行了完善，使复合材料具备一定的可设计性。 论文研究表明，在适当的工艺条件下，水热法制备的PZ-T陶瓷粉纯度高，粒度分布窄，平均粒度为0.5μm，适合于溶液复合。通过陶瓷颗粒对PVDF吸附量的大小的比较确定乙醇为分散溶剂，同时以超声震荡来提高陶瓷颗粒分散的均匀性。实验发现在100Mpa下成型的样品的致密度比无压热处理的要高出近10个百分点。在此基础上，发现在PVDF／PZT体系中引入少量导电聚合物PAn并使其均匀分布于材料内部时提高了陶瓷相的极化率和压电复合材料的压电性能，并且根据介电常数介电损耗及与温度关系的分析可知，添加少量PAn的PZT／PVDF压电复合材料具有更宽的温度使用范围，温度依赖性小。性能测试结果表明，当PZT、PVDF、PAn三相体积比的含量为55％、0.45％、5％时，材料的压电常数最高，达到68pc／N。而且经过理论计算与比较，当以下三个参量取下列值时，即陶瓷颗粒形状因子n=5、极化率α=0.6、结构因子q=0.3时，实验数据与理论计算吻合较好。更多还原

【Abstract】 PVDF/PZT piezocomposite consisting of piezoelectric ceramic and polymer was made according the connection mode, volume fraction ratio or geometric distribution mode. This kind piezocomposite not only possesses properties of the piezoelectric ceramic and the polymer, but also overcomes the disadvantage of each single material. It contains many fine properties such as the high piezoelectricity, low brittleness, density and dielectric constant. And it also can be easy made into various shape products and thin slice. But the disperse degree of PZT ceramic particle in the PVDF is an exigent problem to be solved. The disperse degree of the ceramic can greatly affect uniformity of the composite, which limit the poling voltage and affect the piezoelectricity. In this paper, the relationships among constitutes, microstructures, dielectric and piezoelectric properties were calculated by employing the Banno Unit Cell mode; PZT ceramic were synthesized by the hydrothermal method and the appropriate solution was selected according the adsorption of PVDF on the ceramic particle surface; Then, relationships between the disperse degree and the fabrication process were studied. Base on these, the PZT/PVDF composites intermingled some PAn were prepared and the microstructures were investigated. At last, the Banno Unit Cell mode was proved and improved by the experimental data in order that the design of piezocomposite was more scientific and accurate.The research results show that the PZT ceramic particle with high purity, narrow granularity disperse, so this kind PZT ceramic particle is suitable to prepare the piezocomposite. Then the ethanol was selected to mix the PZT and PVDF. The mixed solution was ultrasonically dispersed to improve the dispersion degree. After that, the sample was pressed into shape and annealed. And it also found that the relative densities of the samples annealed under lOOMpa were 10 percent above those of the samples annealed without pressure. Based on this fabrication process, the PAn was introduced to enhance the uniformity of the composite, thus the piezoelectricity was greatly improved and the poling voltage can be lowered. At the same time, the dielectric propertiesunder different temperature were investigated, it was found that the dielectric properties of PZT/PVDF piezocomposite with some PAn changed slowly from 25C to 250C. The maximum of the piezoelectric constant d33 is 68pc/N when the volume fraction of PZT, PVDF, PAn is 0.55, 0.45, and 0.05 respectively. Finally, ,when the n , a , p are 6, 0.6, 0.3 respectively, the calculation value can agree well with the experimental data.更多还原