Dielectric and electromechanical properties of modified cement/polymer based 1–3 connectivity piezoelectric composites containing inorganic fillers

Here the modified cement/polymer based 1–3 piezoelectric composites containing inorganic fillers were prepared. The influences of filler content and composite thickness on dielectric and electromechanical properties of the composites were investigated. The results indicate that the composites with fillers of graphite and strontium ferrite (Sr-ferrite) have larger static relative dielectric constant and smaller dielectric loss than those with silicon powder. The strontium ferrite can improve the thickness electromechanical coupling property of the composites. When the strontium ferrite content is 5 wt.% of the cement/polymer matrix, the piezoelectric composite has the largest thickness electromechanical coupling coefficient of 64.27% and the smallest mechanical quality factor 8.64. The graphite filler shows a certain suppression effect on the planar resonance of the composites. The coupling effects between the planar and thickness modes of the composites were reduced by decreasing the composite thickness, and pure thickness mode resonance can be obtained at a small composite thickness.