Study On The Preparation And Properties Of The Pyroelectric Lead Zirconate Titanate Organic Composites

Pyroelectric infrared sensors have been extensively studied in the field of thermal detection and imaging of objects, because of the advantages of high sensitivity at long-wavelength and room-temperature operation without cooling system. The PZT pyroelectric ceramics have been prepared by traditional solid method, and the powder of the PZT is prepared by ball milling. The specimen of PZT/PVDF composites is prepared by hot press method, and the pyro, piezo, ferroelectric and dielectric properties are studied. Meanwhile, theoretic analysis has been concluded, and Fd has been calculated. The main research is listed as follow:The PVDF pyroelectric thin films are prepared by Uniaxial-Drawing. The results show that the optimum processing for preparing pyroelectric PVDF thin films: the drawing-temperature is 80℃, with the ratio of drawing at 5 and the anneal temperature at 120℃. The PVDF thin films prepared in this method have a pyroelectric coefficient p= 0.3×10-8C/cm2·K, with the piezoelectric coefficient d33 =9 PC/N, tanδ=0.015,εr =12.The pyroelectric PZT ceramics are prepared by solid method, and the vanishing phenomenon of constriction of the polarization are discussed through SEM, XRD, XPS. The results show that the grain boundary bear P type conductance because of the aggregation of the excess Mn. P type conductance has the same trend as the amount of Mn aggregation. The more the amount of Mn is, the more likelihood the domain would reverse.The pyroelectric PZT/PVDF composites of 0-3 connectivity are prepared by hot press method. The surface morphology and microstructure are discussed through SEM, XRD. The affects of the ceramic volume, the polarization temperature and the polarization voltage on the pyro, piezo and dielectric properties are discussed. The results show that when the ceramic volume reaches to 0.47, there is a maximum value of both the pyroelectric coefficient p and the detectivity figure of merits Fd , the pyroelectric coefficient p is 9.58×10-8C/cm2·K, with detectivity figure of merits Fd at 13.5×10-5Pa-1/2, comparing with the PZT ceramics, the Fd has been increased by 35%.Ferroelectric ceramic-Ferroelectric polymer composites have been studied theoretically, and the expression of pyroelectric coefficient has been deprived for 0-3/1-3 type and 0-3/3-3 type composites.