Kamel, T: Poling and Switching Of Pzt Ceramics

The polarization is the true measure of the degree of ferroelectricity. Generally, ceramic materials with high value of remanent polarization show usable piezoelectric effects. Accordingly, electric poling is one of the crucial intermediate stages of the manufacturing process of the piezoceramics devices. In this thesis, the ferroelectric, pyroelectric and piezoelectric properties and aftereffects in soft and hard PZT are studied. The properties can be influenced by various parameters either extrinsic such as an applied electric field or intrinsic such as grain size. The main objective of this PhD thesis is to understand the polarization phenomena of the PZT ceramics and consequently the appropriate poling conditions can be adjusted to yield the optimum dielectric and piezoelectric performance for commercial piezoelectric actuator devices. Although switching in ferroelectrics is well known phenomenon, many accompanying effects remain not well understood. The thesis treats some unusual switching behaviors in PZT ferroceramics.