Sol-gel-derived PZT fibers: development and limitations

Fine scale lead zirconate titanate (PZT) fibers were fabricated from sol-gel processed viscous 'sol' using spinning methodology developed for the continuous production of glass and carbon fibers. Subsequent drying and firing at temperatures above 700 degrees Celsius resulted in phase pure perovskite fibers with diameters ranging from 30 to 70 micrometers. The dense fibers were comprised of sub-micron grains at sintering temperatures below 1000 degrees Celsius, growing to 2 - 3 micrometers at 1200 degrees Celsius. The dielectric properties of the sol-gel derived fibers were comparable with that of bulk ceramics for both undoped and modified PZT compositions. Relevant to mechanical properties, however, the fine scale PZT fibers exhibited fracture strengths on the order of 50 MPa, well below that of structural fiber materials, e.g. Al ₂O ₃, limiting their potential use in active structural composites.