CERAMIC PARTICLE-SIZE DEPENDENCE OF DIELECTRIC AND PIEZOELECTRIC PROPERTIES OF PIEZOELECTRIC CERAMIC-POLYMER COMPOSITES

Composites with 0-3 connectivity were fabricated from barium titanate and phenolic resin powders. These composites were investigated for dielectric and piezoelectric properties with the active particle size. Under the condition of the same density and ceramic/polymer volume ratio, the dielectric constants and piezoelectric coefficients of composite increase as the ceramic particle size in composite increases. The surface layer model was used to explain these phenomena in our composite system and was confirmed experimentally. The thickness and dielectric constant of the surface layer of the powder prepared by grinding the sintered barium titanate ceramics were 1.59 μm and 105. When the ceramic particle size is larger than about 100 μm, the properties of the composite were nearly independent of size.