Presentations by Purdue Materials Students -- William F. Shelley Jr. & Erica D. Cattanach
William Shelley and Erica Cattanach
Presentation #1: Texture and Anisotropy in Piezoelectric Ceramics
William F. Shelley Jr.
The properties of piezoelectric ceramics, namely lead zirconate titanate (PZT), are widely known, however, the relationship between the properties and the texture of the ceramic are not well known. The present research studies the degree of texture in Navy II PZT (Channel Industries) and the mechanisms of introducing texture into piezoelectric ceramics. X-ray diffraction was used to qualitatively observe texture in Navy II PZT, and fracture toughness was studied through Vickers indentation and four-point bend tests. Fabrication of oriented green bodies is also being studied in hope of tailoring the electrical and mechanical properties of piezoelectric ceramics through powder processing techniques.
Presently the technique of centrifugal casting is being applied to attempt to achieve layered ceramics with varying amounts of lead titanate at the one extreme, to lead zirconate at the other, with intermediate layers in the realm of common PZT compositions. The advantage of such a layered structure is more strain available upon excitation of the piezoelectric. Difficulties have been to get good suspensions of the ceramics in order to cast the layers. Both electrostatic control and steric control have been employed to try to achieve such suspensions. Initial results of the layered ceramics failed to sinter through, leaving a soft core. More work is planned to overcome this and other problems.