Particle size dependence of piezoelectric and acoustical response of a composite hydrophone

Abstract Ceramic-polymer composites composed of highly anisotropic modified lead titanate ceramic and polymer have been prepared utilizing 0–3 connectivity pattern. The composites were formed using ceramic filler powders having five different particle sizes (in the range 5–200 microns). These were found to possess lower densities (2.8 to 4 gm/cm3) and lower relative dielectric constant ∼ 150. Under the condition of fixed density and ceramic/polymer volume ratio, the dielectric constant and the piezoelectric charge constant were found to increase with increasing particle size of the ceramic used. However, these properties were not altered when the particle size of the ceramic exceeded 150 microns. These results could be explained in terms of the existence of surface layer. Three tubular sections cast out of these composites were used for fabricating the hydrophones. The receiving sensitivity of these hydrophones was evaluated using comparison calibration by pulse calibration technique. The measured values ...