HYDROPHONE SENSITIVITY OF POROUS PB(ZR, TI)O-3 CERAMICS

Porous lead zirconate titanate ceramics exhibiting 3-3 connectivity for a considerably wide porosity range, i.e., 0 to more than 70%, were prepared by a unique method using spherical organic materials, poly-methyl methacrylate spheres and polystyrene foams, as pore-forming substrates. The hydrophone sensitivity was measured as well as dielectric and piezoelectric properties. Dielectric constants and 3-1 mode piezoelectric properties agreed with the theoretical predictions, while 3-3 mode properties did not. Hydrophone sensitivity increased around the resonant frequencies. Sensitivity depended slightly on frequency as the porosity increased. Porous PZT is thought to be suitable for a wide-frequency-range hydrophone.