Fabrication and characterization of BST 60/40/PVDF ceramic-polymer composite

Abstract

In this paper BST//PVDF composites with 0-3 connectivity were prepared from (Ba0:6Sr0:4)O3 (BST60/40) ceramic powder and polyvinylidene fluoride (PVDF) powder by a hot pressing method, for different concentration of the ceramic phase (cV ). 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 cV >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 cV >20% cannot be indexed as composites with 0-3 connectivity.