Progress towards ultrasound applications of new single crystal materials

In recent years, single crystal materials with better piezoelectric properties than the existing ceramics have become available. These new materials will potentially provide improved performance in ultrasonic applications such as NDT, sonar and biomedical diagnosis. In order to select the best material and optimize transducer design, comparison must be carried out. However, due to material and transducer fabrication costs, initial comparisons can be based on simulation. In this paper, a comparison is reported between transducers based on the single crystal lead magnesium niobate-lead titanate (PMN-32% PT) and the ceramic lead zirconate titanate (PZT-5H). Material performance is assessed both for single materials and piezoelectric-polymer composite configurations by defining the relevant piezoelectric parameters. Furthermore, the effect of such parameters on the performance of different ultrasonic transducers is illustrated. Practical limitations are also discussed. We conclude that the new single crystal material will be capable of outperforming the present widely used ceramic for almost all practical applications.