【作者】 徐磊；

【导师】 周静；

【作者基本信息】 武汉理工大学 ， 材料学， 2010， 硕士

【摘要】 压电材料利用其正逆压电效应可主动调节其形变或输出电信号而在智能结构中获得广泛应用。压电纤维具有较高的压电应变常数、轴向机电耦合系数及好的各向异性等特点可独立与有机物复合用于医疗超声、水声换能或航空、航天领域的自适应表层。本文采用塑性聚合物方法制备PMnS-PZN-PZT压电纤维,排列-浇铸法制备1-3压电复合材料,系统研究了塑性泥料及压电纤维的的制备工艺,研究了环氧树脂的固化条件,讨论了树脂对压电纤维性能的影响以及纤维长径比对复合材料结构、性能与振动模式的影响。具体工作及结论如下：1、采用塑性聚合物方法制备了PMnS-PZN-PZT压电纤维,研究了粉体粒度、有机物含量及烧结工艺条件对泥料流变学特点及纤维结构和性能的影响。结果表明：陶瓷粉体球磨20h,聚乙烯醇加入量为0.56 wt%,丙三醇加入量为3.33 wt%时,泥料具有最好的塑性,此时,泥料的Zeta电位绝对值最大。1240℃,保温6h制备的压电纤维为完全的钙钛矿结构,晶粒间结合紧密,晶粒大小均匀。抗拉伸强度为16.5 MPa,具有脆性断裂的特点,而纤维素坯的力学性能则具有典型的塑性变形特点,说明塑性聚合物方法可制备高致密度高力学强度的压电纤维。2、研究了夹持状态对纤维铁电性能的影响,结果表明,压电纤维处于自由状态时,剩余极化强度和矫顽场分别为85.4μC／cm2和8.5 kV／cm,采用环氧树脂浇铸夹持之后,剩余极化强度和矫顽场分别为39.2 gC／cm2和15.0 kV／cm,说明夹持状态对纤维的铁电性能产生很大的影响,由漏电流测试结果表明,夹持利于纤维表面漏电流的降低,同时也降低了纤维的自由形变。3、将PMnS-PZN-PZT压电纤维采用排列-浇注法制备了1-3型压电复合材料,研究了复合材料的固化工艺和极化条件,分析了长径比(t/d)对复合材料压电性能的影响。结果表明,复合材料的g33与kt/kp明显高于其相应块体陶瓷材料,说明了纤维用于1-3复合材料具有很好的各向异性。纤维长径比(t／d)对复合材料的压电与介电性能产生很大的影响,当t／d=2时,复合材料的性能最佳,具有单纯的厚度振动模式。更多还原

【Abstract】 Piezoelectric materials are being extended in smart structures for its positive-inverse piezoelectric effect to adjust deformation or electrical output signal initiatively. Piezoelectric fiber has more merits, such as higher piezoelectric constant, larger mechanical-electronical coupling coefficient, and better anisotropism, and it could be used to composite with polymer for medical ultrasonic, underwater transducer or self-adoption surface of aviation, spaceflight applicationIn this article, PMnS-PZN-PZT fibers were fabricated by viscous polymer processing (VPP),1-3 piezoelectric composites were prepared by arranging fibers and casting epoxy resin. The preparation process of plastic ceramic mud and piezoelectric fiber and the conditions of epoxy resin curing are studied. The influences of the resin on the properties of piezoelectric fiber and the aspect ratio of fiber on the structure, properties and vibration patterns of composite material were discussed. Specific work and conclusions are as follows:(1) Piezoelectric materials with better properties were prepared by VPP for PMnS-PZN-PZT piezoelectric fibers. The influence of organic content of the mud compound on the preparation of the fiber and the sintering conditions on the structure and performance of fibers were analyzed. The results show that the optimal formula for the mud:the dosage of polyvinyl alcohol in the ceramic powder is 0.56 wt%, glycerol addition is 3.33 wt%, the value of zeta potential of ceramic mud is the largest. The optimum sintering temperature of fiber is 1240℃, holding for 6h. The ultimate tensile strength of fiber is to 16.5 MPa with brittle fracture and perovskite phase, and the grains combined with tight with uniform size. the piezoelectric fiber with high density and high mechanical strength could be prepared by the method of VPP for the green fiber presenting plastic.(2) Restrained state on the ferroelectric properties of fiber is studied. The remnant polarization and coercive field of piezoelectric fibers in the free state were 85.4μC/cm2 and 8.5 kV/cm respectively, while the remnant polarization and coercive field of fibers in restrained state were 39.2μC/cm2 and 15.0 kV/cm respectively. So the restrained state has a huge impact on ferroelectric properties of the fibers. The restrained state could reduce the leakage current of the surface of fiber and free deformation from the result of leakage current test. (3) The curing process and the polarization conditions of composites made by the way of arranging-casting were studied, and the effect of fiber aspect ratio (t/d) on the piezoelectric properties of composite materials was analyzed. The g33 andκt/κp of composites were higher than the ceramic bulk and fiber, and the 1-3 composite has better anisotropic. The ratio (t/d) of fiber has a large impact on the piezoelectric and dielectric properties of composite. When t/d=2, the composite has the best properties with single thickness vibration mode.更多还原