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[September 2009]
MTC Announces Piezoelectric Composite Components For Undersea Applications
Morgan Technical Ceramics (MTC) has announced the introduction of its Piezoelectric composite components for use in a wide range of undersea applications, including conformal sensors and detectors for ships and deployable vehicles, as well as in large-area arrays for undersea exploration.
Components manufactured with MTC’s Piezocomposite materials are said to offer significant improvements over traditional transducer materials.
MTC’s Piezocomposite material consists of a Piezoelectric ceramic in an electrically-inactive polymer matrix. It is specifically formulated with high coupling values and high dielectric properties. Combining the Piezoelectric ceramic with polymer filler results in a material with an overall density that better matches the medium through which the sound waves travel. This results in lower acoustic impedance, higher efficiency and energy transfer through water and reduced lateral mode coupling within the acoustic device. The arrays can be phased electrically, going from element to element, in a solid state, with no moving parts.
The Piezocomposite materials are being used in many different undersea vessels, including submarines and other manned vessels, as well as autonomous underwater vehicles (AUVs) and remotely operated underwater vehicles (ROVs).
AUVs are robots that travel underwater and are typically used to conduct hydrographic surveys and to look for airplane wreckage, shipwrecks and antiquities. They are also widely used for military purposes, including mine hunting. The non-autonomous ROVs, powered from the surface by an operator or pilot using a control umbilical, are typically used for undersea exploration, checking on the condition of undersea pipelines, using optics or other ultrasound modalities. Side-scan sonar using the Piezocomposites can obtain extremely high resolution images at frequencies ranging from 200kHz to about 800kHz.
The Piezocomposite materials reduce the cross coupling that typically occurs between different modes in the ceramic of conventional transducers, enabling sonar components to respond more precisely and predictably. In addition, components manufactured with MTC’s Piezoelectric composite materials reduce spurious activity, offering higher transmit and receive efficiency. They also provide lower acoustic impedance and improved transducer bandwidth compared to those made only of conventional Piezoelectric ceramics.
Unlike traditional side-scan arrays, which must use various attenuative materials to suppress channel-to-channel interference or cross coupling, the polymer fill in the Piezocomposites has attenuating properties that are maximised for each design, and does not need further suppression. Also, the traditional transducer manufacturing process involves placing thin bars of PZT material in a linear array pattern, much like the tines of a comb. Moving to Piezocomposite materials allows fabricators to make one long plate of material that can be electroded with an array pattern, which greatly simplifies the transducer manufacturing process as well as improving their acoustic signal. The transducers exhibit better resolution and a reduction of cross-talk (element to element interference). In addition, Piezocomposites tend to have less mass and this weight reduction can be a significant benefit. The elimination of complexity in manufacturing can lower costs compared to traditional side-scan transducers.
www.morgantechnicalceramics.com
ENDS