PZT压电纤维的制备与性能研究

【作者】 杨杰；

【导师】 刘兴钊；

【作者基本信息】 电子科技大学 ， 电子信息材料与元器件， 2008， 硕士

【摘要】 压电材料是指由于静压力变化或温度改变而产生相应感应电荷变化的材料。这种材料能够自适应环境的变化实现机械能和电能之间的相互转化,具有集传感、执行和控制于一体的特有属性,是智能材料系统中的主导材料。近几十年来,随着压电器件应用领域的不断扩大,对其性能也提出了一些新的要求,其中1-3型压电复合材料采用纤维形压电相和有机材料复合,这不仅使材料具有良好的柔顺性和机械加工性能,而且也使其具有各向异性的驱动性能。因此在智能材料与结构中有着广泛的应用前景。压电陶瓷纤维是1-3型压电复合材料中最为重要的一个组成部分,其制备与性能研究也引起了越来越多的关注。目前,主要的压电纤维制备法是纺丝法和割模一浇铸法（the dice-and-fill method）。但是纺丝法所制备出的纤维均匀性和致密性比较差,而割模-浇铸法制备出的陶瓷纤维长度不大,这使得它们所制备的PZT陶瓷纤维在实际应用时受到很大限制。针对纺丝法所制备的纤维致密性差而割模-浇铸法制备的纤维长度不足的缺点,本论文尝试采用氧化物粉末装管法（the Oxide Powderin Tube）来制备压电陶瓷纤维。实验中,首先以乙酸铅（Pb（CH₃COO）₂·3H₂O）、钛酸四丁酯（Ti（OC₄H₉）₄）、硝酸锆（Zr（NO₃）₄·5H₂O）为原料,采用Sol-Gel工艺,制备出了颗粒分散性好、粒径介于40～80nm之间的PZT超细粉。PZT粉体的烧结实验表明:Sol-Gel法制备PZT粉末的合成温度（600～700℃）比传统的固相反应烧结法要低得多。这一方面可避免过高的煅烧温度所造成PbO的挥发,另一方面可抑制粉体生长并聚集起来形成硬团聚体,有利于制备性能优良的PZT粉末。然后以PZT粉为原料,采用氧化物粉末装管法制备了PZT压电陶瓷纤维。SEM分析显示该陶瓷纤维呈圆柱状,直径约为250μm。通过研究烧结温度对PZT陶瓷纤维的断面微结构及铅含量变化的影响,揭示PZT陶瓷纤维的合适烧结温度为1000℃。XRD分析表明:此温度下烧结的陶瓷纤维呈单一的钙钛矿结构。对其所作的电性能测试也表明,纤维具有优良的压电性能。分析结果说明:采用氧化物粉末装管法制备的陶瓷纤维大小均匀、结构致密、具有高长径比,克服了纺丝法和割模-浇铸法的缺陷。更多还原

【Abstract】 Piezoelectricity is a phenomenon when a mechanical stress is applied to some piezoelectric material; electrical charges appear between its two opposite sides. Conversely, if an electrical field is applied to this material, it will generate mechanical strain. Also, for material showing Pyroelectric properties, electric charges will appear under the effect of temperature. According to these proprieties, piezoelectric ceramics have been used as sensor and actuator materials in many practical fields, especially in smart material and structural systems, because they have the ability to transform energy from electrical to mechanical and vice versa. As the application fields of piezoelectric ceramics are continuously expanding, these devices are required to be variable, both in terms of their functionality and their shape. The 1-3 connectivity piezoelectric ceramic fiber-polymer composite materials could be widely applied in smart materials and structures, since they have more toughness, performances and orthotropy.Recently piezoelectric ceramic fibers have attracted attention as regards particular applications such as in parts of 1-3 composites. In order to realize such potential applications, the fabrication of fibers is becoming an increasingly important issue. At present, the predominant fabrication route is based on the cellulose spinning process and the dice-and-fill method. Unfortunately, the cellulose spinning process can not fabricate the dense and uniform piezoelectric ceramic fibers. The dice-and-fill concept is difficult to apply to high frequency composites because of the ultrafine lateral scales required for efficient operation. Here, we describe a new technique based on the Oxide Powder in Tube （OPIT） procedure to produce ceramic fibers.First of all, PZT ceramic powders were prepared by a modified Sol-Gel method. The starting materials were lead acetate trihydrate （Pb（CH₃COO）₂·3H₂O）, tetrabutyl titanate （Ti（OC₄H₉）₄）, and zirconium nitrate (Zr（NO₃）₄·5H₂O. The microstructure of the nanocrystalline powder was characterized by XRD and SEM. The results show that grains of the PZT nanocrystalline powder are spherical and non-aggregated. The average grain size is 40～80nm. Compared with conventional solid reaction method, PZT powders prepared by a modified Sol-Gel method have the advantage of low temperature synthesis, stoichiometric composition precision and homogeneous distribution.Then with the PZT ceramic powder, the PZT ceramic fibers with a diameter of about 250μm were obtained by using the Oxide Powder in Tube （OPIT） procedure. The SEM morphology showed that the PZT fibers were dense and uniform. The X-ray diffraction patterns showed that the ceramic fibers were pure perovskite structure. Compared with conventional fabrication process, PZT ceramic fibers prepared by the OPIT method have the advantage of dense ,uniform and high height-to-width ratio.更多还原