Design, development and characterization of a mid-frequency (35 khz) tonpilz transducer array from 0.675PMN-0.325PT piezoceramics

Abstract

A mid-frequency tonpilz transducer array was designed and analyzed by finite element method using commercial ATILA code and constructed using piezoceramic rings with lead magnesium niobate (PMN)-lead titanate (PT) composition. The morphotropic phase boundary (MPB) 0.675Pb(Mg1/3Nb2/3)O3-0.325PbTiO3 composition was chosen to obtain higher performance from the transducer due to the superior dielectric and electromechanical properties of the MPB compositions. A pure perovskite phase was obtained from the ceramics. Piezoelectric charge coefficient (d33) was measured as 435 pC×N-1. Single tonpilz element and an array consisting of 7-unit array were constructed and later potted in polyurethane for underwater measurements. A second array was also constructed for comparison from commercial hard Pb(Zr,Ti)O3-PZT ceramics. The longitudinal piston mode vibration frequency of the tonpilz transducer was measured around 33 kHz in air and around 35 kHz in water. The PMN-PT based array was found to have a comparable transmit performance and a superior receive performance compared to PZT.