【作者】 唐耀波；

【导师】 周静；

【作者基本信息】 武汉理工大学 ， 材料物理与化学， 2011， 硕士

【摘要】 压电纤维不仅可作为压电复合材料的功能相而广泛用作传感器和驱动器,而且可直接应用于微纳米器件,实现换能器的微型化。它的出现,极大的扩展了压电材料的应用范围。Nao.5Bio.5Ti03(NBT)是一类具有较高压电系数和机电耦合系数性能的无铅压电材料,可望成为PZT应用的无铅化替代物。利用课题组已研制成功的压电性能较好的KNBT陶瓷组成,采用塑性聚合物方法制备压电纤维,采用排列-浇注法制备压电纤维复合材料。系统地研究了球磨时间对粉料性能及纤维力学性能的影响,分析了陶瓷固含量对压电纤维结构的影响,研究了不同聚合物对复合材料结构的影响,探讨了纤维间距对叉指型电极复合材料铁电性能影响。主要研究内容及结论如下：1、研究了球磨时间对粉料粒度及比表面积的影响,分析了粉料颗粒度对纤维力学性能的影响。结果表明,随着球磨时间延长,粉料粒度降低,比表面积增大,Zeta电位升高。粉料粒度对纤维力学性能产生大的影响,当平均粒度0.37μm左右时,可获得最大抗拉强度的压电纤维,其抗拉强度达40.01MPa。2、采用塑性聚合物方法制备了KNBT压电纤维,研究了陶瓷固含量、烧结工艺和极化工艺对纤维结构和性能的影响。结果表明,陶瓷固含量为83%时,纤维结构最致密。最佳烧结温度为1130℃,保温时间为2h,制备的KNBT纤维为完全的钙钛矿结构,且结构致密、晶粒大小均匀。最佳极化工艺参数为：极化时间20 min,极化温度120℃,极化电压3.5 kV/mm,单根纤维压电常数d33达到69 pC.N-1。3、采用排列一浇注法制备了压电纤维复合材料,研究了不同聚合物对复合材料结构的影响,研究了纤维间距对叉指型电极复合材料铁电性能影响。结果表明,环氧树脂比聚丙烯更适合于作为基体材料,随着纤维间距的缩小,复合材料剩余极化变大,紧密排列时Pr=6.9μC/cm2。更多还原

【Abstract】 Piezoelectric fibers not only can be the main phase of the composites to be used as sensors and actuators, but also can be used in micro devices. Their appearances have widely expanded the applications of piezoelectric materials.Na0.5Bi0.5TiO3 (abbreviated as NBT) is a lead-free piezoelectric ceramics with good piezoelectric properties and high electromechanical coupling coefficient, can be a alternative to replay PZT. We use the KNBT ceramic system with a good piezoelectric properties which had studied by our lab, the fibers were fabricated by viscous polymer processing.1-3 piezoelectric composites were prepared by arranging fibers and casting epoxy resin. We discuss the influence of the balling time on the particle distribution and the surface area, analyze the mechanical property of fiber with different particle size, discuss the ferroelectric properties of interdigitated piezoelectric composites with different fiber spacing. Specific work and conclusions are as follows:1、We discuss the influence of the balling time on the particle distribution and the surface area, analyze the mechanical property of fiber with different particle size. As a result, when the milling time extend, the particle size of the powders reduce, the surface area increase, Zeta potential increase. The particle sizes of the powder have high influence to the mechanical property of the fibers. The fibers made by the powder of the average particle size 0.37μm have the highest ultimate tensile strength,40.01MPa.2、Piezoelectric materials with better properties were prepared by VPP for KNBT piezoelectric fibers. The affects of sintering condition on fiber structures and properties were analyzed. And the best sintering condition was done at 1130℃for 2 h. The fiber structure was dense, and the crystal size was uniform. The optimal poling condition was processed on time of 20 min, temperature of 120℃, and electric field of 3.5kV/mm. The piezoelectric strain constant was 69pC.N-1.3、KNBT piezoelectric fibers/epoxy resin composites were made by the arranging-casting technique. The remnant polarization and coercive field of single KNBT fiber in restrained state were 32.5μC/cm2 and 3.8kV/cm, while the remnant polarization and coercive field of KNBT piezoelectric fibers/epoxy resin composites of the fiber volume fractionΦ30% were 6.3μC/cm2 and 3.7kV/cm. The fiber spacing had prodigious effects on the ferroelectric properties. With decreasing the fiber spacing, the remnant polarization increased.更多还原