PMN-PT and PZN-PT single crystals are finding increasing acceptance in biomedical imaging and actuator applications because of their superior piezoelectric performance in comparison to PZT ceramics, which have been the commercial material of choice for acoustic transduction for the past 50 - 60 years. This thesis addresses the potential of these piezocrystals for underwater imaging systems, taking into account their practical capabilities as well as the benefits of their enhanced performance. The text begins with a theoretical comparison of the material properties of the three piezoelectric materials discussed in this thesis; PMN-PT, PZN-PT and PZT-5R. Basic prototypes were manufactured to practically measure the performance of each material in bulk form, piezocomposite structures and within acoustic transducers. These devices showed the broader bandwidth and greater sensitivity achievable from PMN-PT composite. More complex transducer designs such as the addition of impedance matching circuitry to a piezocrystal composite transducer, integration of a PMN-PT piezocomposite transducer into a mechanically scanned sonar system, and the development of a single crystal parametric acoustic array highlighted potential applications for PMN-PT single crystal in underwater sonar. Moreover, to fully understand the capabilities of the material, a series of experiments measuring the ageing, variation of material properties within a batch of samples, stability during high power driving and behavioural changes with temperature have also been carried out. It is concluded that PMN-PT single crystal is potentially viable for applications where broader bandwidth and spatial resolution are highly desirable but that the cost of the material may limit the likelihood of this material replacing PZT ceramic in all sonar applications.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:488701 |
| Date | January 2007 |
| Creators | Wallace, Michelle F. |
| Publisher | University of the West of Scotland |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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