Properties of fine scale piezoelectric PZT fibers with different Zr content

Smart materials containing piezoelectric fibers have a large potential in sensoric, actuatoric and ultrasonic transducer applications. Fine scale PZT fibers with five systematically adjusted Zr/Ti ratios ranging from x=5842 to 4852 have been prepared using a sol–gel route. The fibers were embedded in a polymer matrix to produce 1-3 composites and the effective piezoelectric and dielectric coefficients were measured. An analytical model was used to extract the corresponding values of the fibers from the effective material properties. The dependence of the coefficients on the Zr/Ti ratio shows a pronounced maximum at x=5347. This correlates with an analysis of the phase content. For x=5347 the fibers consist of 31% rhombohedral and 69% tetragonal phase, whereas the content of rhombohedral phase is 100 and 7% for x=5842 and 4852, respectively. For x=5347 maximum values of ε33T=1200 and d33=127 pm/V were found. The latter one is about 50% of the value of corresponding bulk materials.