Papers by Author: Dagmar Hülsenberg

Abstract: In this study PZT-green fibres containing 50, 54 and 58 vol.% PZT powder were extruded. The influences on the mixing torque, the apparent shear rate and the extrudability were investigated and a theoretical maximum powder loading content was calculated using a model introduced by Frankel and Acrivos. The influence of powder loading content on the microstructure (porosity and grain size), the phase composition and on the final ferroelectric properties of sintered PZT fibres was investigated. The measurements revealed that the production of PZT fibres with homogeneous properties requires a minimum powder loading content of 58 vol.% PZT powder.

Abstract: Lead zirconate titanate (PZT) fibres with diameters between 70 and 300 μm have been extruded and sintered at 1200°C in a PbO-enriched atmosphere. Subsequently, the influence of fibre diameter on the microstructure (porosity and grain size) was investigated. The measurements revealed that with decreasing fibre diameter, the porosity decreases whereas the grain size increases. The influence of these microstructural differences on the piezoelectric properties was evaluated using a novel characterisation procedure for single PZT fibres. Fibres with an as-extruded diameter of 100 μm developed an average maximum strain of 3800 ppm at an applied electrical field of 3 kV/mm and exhibited the best performance for all fibres processed with the chosen sintering parameters.