Development of ultra-fine scale piezoelectric fibers for use in high frequency 1-3 transducers

Lanthanum substituted lead zirconate titanate (PLZT) fine scale piezoelectric fibers (<60 μm) were fabricated for use in high frequency ultrasonic imaging transducers. Single fiber filaments, ranging from 10 to 60 μm in diameter, were produced in a continuous fashion using metal alkoxide sol-gel technology. Microstructural and electrical characteristics of these fibers were determined under different pyrolysis conditions to obtain crack free, dense fibers. Final grain sizes were 1-1.5 microns at sintering temperatures of 1200°C for 30 minutes. Permittivities for PLZT fibers improved to 1200 by using CO, H₂O and N₂ atmospheres during pyrolysis to control organic burnout. PLZT compositions were incorporated into 1-3 type fiber/polymer composites. Preliminary data on 1-3 composites made using these fibers confirm single fiber dielectric constant determinations and have ceramic volume fractions up to 40%