Effects of Slurry Properties on the Crack Formation in Ceramic Green Sheets during Drying

Abstract

The slurries studied were characterized by a conventional apparent viscosity measurement, a constant rate filtration and a stress relaxation test proposed in this study in order to identify the most affective property of a slurry on the crack formation of a green sheet during drying. We evaluated the packing ability of the slurry from the constant rate filtration and stress relaxation rate of a cake form by the stress relaxation test. Slurries were also tape cast, dried at room temperature and then cracks formed in green sheets were observed. Slurry properties were controlled by changing the pH value of the slurry or the additive amount of the binder. It was shown that there is not a good correlation between the apparent viscosity, packing ability of slurry and crack formation in the green sheet, while the number of cracks decreased with an increase in the stress relaxation rate of the cake. The stress relaxation test can be useful to predict crack formation during drying regardless of the slurry preparation method such as the pH adjusted or binder containing slurries.