Fabrication and characterization of BST60/40//PVDF ceramic-polymer composite

Abstract

In this paper BST//PVDF composites with 0-3 connectivity were prepared from (Ba 0.6Sr 0.4)O 3 (BST60/40) ceramic powder and polyvinylidene fluoride (PVDF) powder by a hot pressing method, for different concentration of the ceramic phase (c v). Morphology of BST//PVDF composites was observed by transmission electron microscopy and scanning electron microscopy, whereas the crystalline structure was studied by the X-ray diffraction method. The temperature dependence of dielectric permittivity of BST//PVDF composites was measured in the frequency range of f=10kHz-1MHz. The split-post dielectric resonator (SPDR) was used for the measurements of the real and imaginary part of dielectric permittivity of BST//PVDF composites in the microwave frequency range of f=3-10GHz. It was found, that the dielectric properties of the ceramic-polymer composite for c v >20% change significantly for both small (f=10kHz-1MHz) and high (f=3-10GHz) frequencies. The abrupt increase in permittivity may indicate an excess of the percolation threshold, so the ceramic-polymer composite for the concentrations of the active ceramic phase c v >20% cannot be indexed as composites with 0-3 connectivity.