Studies On Pyroelectric Ceramic Materials Of PZT System With High Properties

Zr-rich PMN-PZT ceramics have properties of high pyroelectric coefficient, low dielectric constantε, dielectric loss tanδand high figures of merit, when occurring FRL-FRH transition. The FRL-FRH transition can be repeated and needn't to be polarized again. These characteristics make the series of ceramic materials promising in the aspect of infrared detection.From the expression of pyroelectric figures of merit: FD=p/Cv(ε·tanδ)1/2, which is the important index to evaluate the integrated performance of pyroelectric materials, we can see that pyroelectric materials with good performance should have a high pyroelectric coefficient, low dielectric loss and appropriate dielectric constant. Manganese-doping can reduceεand tanδof PMN-PZT ceramics, but the influences that the manganese-doping has on the phase composition, microcosmic configuration, and the dielectric, ferroelectric and pyroelectric properties of the Zr-rich PMN-PZT ceramics has not been particularly reported yet. We did the researches on the task our researching department taking. The main work included the studies on the preparation techniques of Zr-rich PMN-PZT ceramics and the systemic studies on the influence of manganese-doping on the phase composition, microcosmic configuration, and the dielectric, ferroelectric and pyroelectric properties of the PMN-PZT ceramics for the first time. We have explained the physical mechanism aiming at the results of the experiments and studied the action of the FRL-FRH transition of PMN-PZT ceramics as well in this paper.The results show that manganese-doping not only can reduceεand tanδof the PMN-PZT ceramics effectively but also can improve the pyroelectric coefficient, which has great significance in improving FD. Basing on this we have developed the PMN-PZT ceramics with good integrated properties: in room temperature,εr=197, tanδ=0.15%, p=3.5×10 -8C/cm2℃and FD=8.7×10-5Pa-1/2; during the FRL-FRH transition,εr=300, tanδ=0.45%, pmax=35×10 -8C/cm2℃and FD=40.5×10-5Pa-1/2. These parameters have already satisfied our task's targets and answered for the demand of making detectors.