Fabrication of Discontinuous Al2O3-Dispersed TZP Fibers by a Sol-Gel Method

Abstract

Discontinuous, polycrystalline Al2O3-dispersed TZP fibers were prepared by the centrifugal spinning of a colloidal ZrO2 sol containing Y and Al nitrates and poly(vinyl alcohol). Factors affecting the rheological properties of the sols, such as sol concentrations, aging, and the amounts and types of additives, were investigated by measuring the shear viscosities. The flow characteristics of the sols were studied in relation to the spinnability by measuring the viscosity with respect to the shear rate. The spinnability was obtained through the addition of a polymer which increases the viscosity to a range of optimum viscosity values for spinning. Aging the sols containing the additives did not noticeably change the sol viscosities at room temperature up to 30 days. The flow behavior of the spinnable sols progressively changed from nearly Newtonian to pseudoplastic with an increase in the sol concentration.