Preparation And Properties Of1-3Type Piezoelectric Composites

Nowadays,1-3type piezoelectric composites have been widely used in many fields such astransducers, hydrophones and energy harvesting due to the characteristics of lower impendence Z,higher piezoelectric constants gh, higher thickness coupling coefficient k_t, obvious anisotropy and soon. According to the present researches of1-3piezoelectric composites, piezoelectric fibers and1-3composites in this study were fabricated by viscous polymer processing and arrangement-castingmethod, respectively. Meanwhile, the effects of the solid content, ceramic composition, ceramicvolume fraction, aspect ratio and temperature on the properties of the1-3composites were studiedsystematically.The fabricated piezoelectric fibers have good density while the proportion of ceramic powder,polyvinyl alcohol and glycerol is30:4:1. Under the best sintering processing, three kinds ofpiezoelectric fibers possess fine linearity, with the diameter of piezoelectric fibers about300⁴00μm,and show a pure perovskite phase structure and high density morphology. With the increasing ofceramic volume fraction, relative permittivity ε_rincreases linearly, while dielectric strain constant d₃₃,thickness coupling coefficient k_t, remnant polarization P_rincreases nonlinearly. When the ceramicvolume fraction is50%, PZT-PMS-PZN piezoelectric composite has good electrical properties:d₃₃=300pC/N, ε_r=613, k_t=0.59，P_r=2.33μC/cm2. Moreover, when the aspect ratio of the piezoelectricfibers is between2and4, the1-3piezoelectric composites have pure thickness coupling resonanceand good electrical performance.As an1-3piezoelectric composite, it owns piezoelectric phase and polymer matrix. Polymermatrix is more sensitive to the temperature than piezoelectric phase, which results in its poorthermostability. From the room temperature to100℃, the parameters of ε_r, dielectric loss tanδ, k_t/kpall increase along with rising temperature. At100℃, the electrical properties of the PZT-PMS-PZNpiezoelectric composite: ε_r=723，k_t=0.71, tanδ=4.0%. Additionally, the analysis of the impedance-phase relationship shows that there is only one clear thickness resonance mode at100℃, indicating itswell temperature stability.In the application of energy harvesting, the properties of piezoelectric vibrators based on1-3piezoelectric composites are investigated in a rotary piezoelectric windmill. Using the ball to strikepiezoelectric vibrators, the generated signals received by oscilloscope were analyzed. The resultsshow that the piezoelectric vibrations are working at unresonant frequencies. On this condition, the value of d₃₃ g₃₃is the most considerable element of the materials for energy harvesting, and1-3piezoelectric composites have the advantages of high d₃₃ g33value. Therefore, such kind of1-3piezoelectric composite is an excellent candidate for energy harvesting.