Rheological characterization and tape casting of aqueous zircon slips

In this work, a commercial zircon flour of 99% purity and mean particle size of 10µm is used. Suspension stabilization process is carried out using the electrostatic stabilization mechanism at pH 11 employing Tetramethylammonium hydroxide (TMAH). Tape casting suspensions are formulated with binding systems obtained by the combination of polyvinyl alcohol with polyethylene glycol, additionally the binding system is added at different binder:plasticizer ratio ranging from 1:1 to 3:1. Suspensions are characterized rheologically determining its type and flow properties by obtaining flow and viscosity curves. Suspensions are tape cast on vinyl-acetate substrates and are dried at room conditions to determine some physical properties of the obtained tapes and to correlate the rheological with the physical properties. The experimental results show that tape casting suspensions have a shear thinning flow type, yield points and flow indexes varying as a function of binder system combination and binder:plasticizer ratio. Also, the binder system has a strong influence on the green tapes characteristics.