James Anthony Brewer

Additive manufacturing of PZT-5H piezoceramic for ultrasound transducers

This paper describes the development of a low-cost, high speed manufacturing process method for the fabrication of piezoelectric ceramic transducer elements in the 1-25 MHz frequency range. A modified multi-layer lithography process, is used to additively manufacture high-resolution netshape ceramic structures by photopolymerizing a ceramic-polymer slurry using structured light patterns. The paper elaborates on the key considerations in the development of the process including the selection and optimization of slurry materials for the deposition of PZT 5H materials, optical exposure parameters, debinding/sintering profiles and post-manufacturing processing. coupling coefficient in the range of 0.52-0.54. Ongoing work includes improvements to materials properties, improved throughput and geometric fidelity.

Dielectric Loss Reduction of Ferroelectric Lead Magnesium Niobate-Lead Titanate Sound Projector Drivers

Improvement of the large signal dielectric loss of a commercial ferroelectirc lead magnesium niobate-lead titanate (PMN-PT) sound projector driver has been achieved without sacrificing other electromechanical properties. Length extensional resonators fabricated from the modified composition have been characterized for dielectric losses, 33-mode electromechanical coupling, and acoustic energy density under uniaxial compressive stress and large signal drive requirements for sound projectors. Selective doping and microstructural control have been used to achieve the desired properties.