Effect of wet-rotating disc milling process for preparation of stable dispersed Al2O3 slurries and dense green bodies

A wet-rotating disc milling was used as a method to prepare ceramic slurry. The rheological measurements of the milled slurries showed that the apparent viscosity of the wet-rotating disc milled slurry was low and the slurry was nearly Newtonian behavior, whereas that of ball-milled slurry was more viscous and the slurry exhibited a very strong shear thinning effect. Furthermore, the internal structure composed of aggregated particles in the slurry of the ball-milled slurry was strong and fragile, whereas that of wet-rotating disc milled slurry was the soft structure due to good dispersion. Also, the relative densities of green compacts prepared by slip casting were measured by Archimedes' method. The relative densities of green compact prepared by the wet-rotating disc milled slurries were higher than those of the ball-milled slurries, and were constant at around 65% without depending on the solids loading. The linear shrinkages of the sintered bodies prepared by ball-milled slurry increased from 14.2% to 21.2% with decreasing the solids loading of Al2O3 slurry. On the other hand, the linear shrinkages of sintered bodies prepared by wet-rotating disc milled slurries were constant at about 11%, resulting that the shrinkage of sintered body was suppressed by preparing well-dispersed and stable slurry with wet-rotating disc milling. (C) 2019 Elsevier Ltd. All rights reserved.