Study On The Effect Of PZT Based Piezoelectric Fibers On The Properties Of 1-3 Composites

1-3 piezoelectric composites combine the high piezoelectric properties of piezoelectric ceramic and the flexibility of polymer. Thus 1-3 piezoelectric composites have more merits, such as higher piezoelectric constant, larger electro-mechanical coupling coefficient, lower mechanical quality factor and smaller acoustic impedance. They are suitable for transducers with high sensitivity, broad and narrow pulse, which have been widely used in medical ultrasonic, non-destructive testing and hydroacoustic transducers.For the applications of 1-3 piezoelectric composites to medical ultrasonic transducer, PZT5, PMnS-PZN & PBS fibers based 1-3 piezoelectric composites were fabricated by VPP. The interrelation of composites among piezoelectric phases, arrangements & properties were studied systematically. And the effects of different composition and volume fraction of piezoelectric fibers on the composites properties were discussed.(1)PZT5,PMnS-PZN & PBS ceramic fibers with diameters of 250μm were fabricated by viscous polymer processing. The affects of ceramic solid content and sintering condition on fiber structures and properties were analyzed. The green body of piezoelectric fiber with better plasticity & intensity could be gotten when the ceramic solid content was 85.71%. And high intensity,compact structure & uniform grain size of piezoelectric fiber could be gotten when sintered at 1190-1280℃for 2-6h.(2)The ceramic volume fractionφhad prodigious effects on properties of 1-3 composites. With increasing the ceramic volume fraction, the relative permittivity constantε^T of 1-3 composites rose linear, and remnant polarization gained prominently. The piezoelectric strain constant d₃₃ mounted up with increasing the ceramic volume fraction. Its radial coupling coefficient kp was less than PZT5 ceramic, and kt>kp. The mechanical quality factor Q_m was much smaller than PZT5 ceramic. The acoustic impedance Z promoted with higher ceramic volume fraction, which was always below the ceramic value.(3)The permittivity constant of 1-3 composites with different ceramic phases were almost reduced 10 times than ceramic respectively. The permittivity loss increased a little. The piezoelectric strain constant d₃₃ and piezoelectric voltage constant g₃₃ of 1-3 composites were comparatively high. The mechanical quality factor Qm reduced respectively. The acoustic impedance Z was about one third of the ceramic value. The properties of piezoelectric composites have the same variation regularity with the piezoelectric fibre properties. So the properties of composites can be improved through the modification of fibre properties.