Effect of Particles Dispersion State and Packing Ability of the Slurry on the Density of Green Body for Ceramics Wet Shaping Processes

Abstract

It is important to control and characterize the particles dispersion and aggregation state in a slurry for ceramics wet forming processes. In these processes the particle concentration of the slurry must be high, thus, it is desired to directly evaluate the particles dispersion state for dense slurries without dilution. In this paper, we discuss the relationship between the density of green body fabricated in tape casting process and the slurry characteristics measured without dilution, such as apparent viscosity (relative viscosity) and the packing fraction of sediment. It was demonstrated that the slurry with the highest packing fraction of sediment yields the green sheet with the highest density, while the slurry with the lowest apparent viscosity (relative viscosity) does not necessarily yield the green sheet with the highest density. It was indicated that the key of slurry characterization for controlling the density of green sheet should be considering the change of the particles dispersion and aggregation state due to thickening and dehydrating of the slurry in tape casting process.