Piezoelectric Ceramic Hydrostatic Sound Sensor.
Patent Application, Filed 5 Dec 90,
DEPARTMENT OF THE NAVY WASHINGTON DC
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This invention relates to a piezoelectric ceramic hydrostatic sound sensor or transducer having one or a plurality of voids and to a method for making such a transducer. Conventional piezoelectric ceramic hydrophones employ relatively incompressible materials such as lead zirconate titanate PZT having the general formula PbO ZrO2 0.52 TiO2 0.48 PZT doped with 6-15 lanthanum oxide, La2O3 PZLT barium titanate, BaTiO3 lead zinc niobiate, PbO ZnO Nb2O5 and lead magnesium niobiate, PbO MgO0.33Nb2O50.67. The electromechanical response of ceramic transducers to hydrostatic pressure variations is only a fraction of their uniaxial electromechanical sensitivity because, due to their Poisson ratio, the lateral force components due to hydrostatic pressure tend to cancel out the axial compression of the material, thereby reducing the electromechanical response to hydrostatic pressure.
- Miscellaneous Detection and Detectors