Processing Methods to Fabricate Reliable Device Elements of PMN-PT Piezoelectric Single Crystals

The objective of this proposal is to demonstrate the feasibility of enhancing the mechanical strength and reducing the manufacturing costs for PMN-PT single crystal elements by proposed mechanical processes. At present time, the surface defects in such multi-domain PMN-PT piezocrystal elements result in mechanical strength degradation. This has limited our ability to fully utilize the tremendous piezoelectric properties of PMN-PT crystal elements, especially for high power applications. The special requirements for the surface preparation of single crystal are different from those of semiconductor or optical components. In the case of piezoelectric crystals both some degree of surface roughness and freedom from defects are needed. Crystal finishing techniques, including surface and edge defect control, wedge and ring machining are key factors that will contribute to successful commercialization of the next generation of piezocrystal transducers and devices. The proposed crystal finishing techniques will be of immediate applicability to the fabrication of crystal elements with improved surface quality. We propose in Phase II to extend the techniques demonstrated in Phase I to mass production. BENEFITS: The work will enhance the mechanical strength for PMN-PT crystal elements by improvements in crystal mechanical finishing processes, especially in the control of surface mechanical defects. The proposed work is of great significance for high drive applications of single crystal for Navy Sonar, sensors, actuators, vibration control, shape control, position control and etc. The work also aims to devise processing methods to reduce the manufacturing cost and to increase reliability of the final transducer products.