Processing and Properties of Co-Extruded Lead Zirconate Titanate Fibers
Ismael, MR; Clemens, F; Wyss, P; Graule, T; Hoffmann, MJ
JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 2012, Band 95, Heft 1, S. 108-116, DOI: 10.1111/j.1551-2916.2011.04851.x
The development of the whole process chain, starting with feedstock preparation and rheological characterization, followed by debinding, sintering, and the final properties is described for the fabrication of lead zirconate titanate (PZT) fibers through the co-extrusion process. The PZT-polymer and carbon black (CB)-polymer feedstocks were prepared using a high-shear mixer and their rheological behavior was characterized by torque rheometry and by the evaluation of viscosity models which consider the influence of the volume fraction of solids on the relative viscosity Based on the rheology of the compounds, a feedstock containing 58 similar to vol% of PZT and another containing 35 similar to vol% of CB were selected for the co-extrusion process. By varying the viscosity ratio between the co-extruded materials, three different co-extrusion investigations were carried out. To detect any defect present in the green co-extruded monofilament composites that may become evident only after debinding, sintering or even at the test stage, X-ray tomography was performed. To establish the developed co-extrusion process chain, the microstructure, and the electromechanical properties of successfully co-extruded and sintered fibers (phi similar to 250 similar to mu m) were compared with fibers produced by conventional thermoplastic extrusion. The extruded fibers revealed a maximum strain of 0.39%, whereas this value was decreased to 0.22% for the co-extruded ones.