Dielectric and damping properties of 0-3 PMN/epoxy composites

0-3 PMN/epoxy composites were prepared by the casting method. The effects of piezoelectric ceramic lead magnesium niobate-lead zirconate-lead titanate (PMN) on curing of epoxy resin were studied by DSC analysis.The researches on dielectric properties show that the dielectric constant and dielectric loss increase nonlinearly with PMN content increasing. The dielectric constant decreases sharply with frequency increasing when the frequency is lower than 10⁵ Hz,which is at tributed to the interfacial polarization in the composite. At high frequency,the dielectric constant changes slightly,which means that the PMN/EP composites have a good high frequency stability. In the testing frequency range,the dielectric loss decreases slightly with the frequency increasing,but the extent is very narrow. DMA analyses indicate that the storage modulus,loss modulus,the peak of the damping loss factor curve and the damping temperature range of composites are all affected by the content of PMN. When the PMN content was 87. 24 wt%,a new peak in the damping loss factor curve at about 90℃ was observed,and the temperature of the new peak did not shift with the testing frequency change. The dielectric loss of composite may contribute to ap-pearance of the new damping loss factor peak.