Sun Huajun

Dielectric and Piezoelectric Properties of 0-3 PZT/PVDF Composite Doped with Polyaniline

Lead zirconate titanate (PZT)/polyvinylidene fluoride (PVDF) 0-3 piezoelectric composites doped with polyaniline (PANI) were obtained by hot-press method. The polarization properties of the composites were characterized by XRD and P-E hysteresis loops at room temperature. And the dielectric and piezoelectric properties were also measured. The results show that the poling of PZT could be effectively carried out and the dielectric constant εr, and dissipation tanδ increase monotonously by increasing the volume fraction of PANI in the composite. The piezoelectric constant d33, and the planar electromechanical coupling factor kp increase while the mechanical quality factor Qm decreases with the increase in the content of PANI. The d33, kp and Qm show the extremum values at 8 vol%-10 vol% PANI.

Characterization of PZT/PVC composites added with carbon black

A new three-phase PZT/C/PVC composite comprising PZT (50vol%), nanocrystalline PVC (50 vol%) and a small volume fraction f of carbon black (C) was prepared by the hot-pressing technique. The dielectric property of the composite as a function of the frequency and the dielectric and piezoelectric properties as a function of the volume fraction f of C were studied. The measured dielectric property demonstrates that a percolation transition occurs in the three phase composites as in normal two-phase metal-insulator continuum media. The dielectric constant varies slightly with f at f<0.1 and increases rapidly when f is close to the percolation threshold at 1 kHz. The optimum properties were obtained for f=0.5 before the percolation threshold in the PZT/C/PVC (50/f/(50−f) vol%) composite with its d33(20 pC/N) being 50% higher than that of the PZT/PVC (50/ 50vol%), and its g33 (47.23×10−3 Vm/N) and Kμ(0.25) much higher than the earlier reported values XRD patterns and P-E hysteresis loops were used to interpret the experimental results.