The ability of the wet jet milling method to pulverize nanosizedalumina suspensions for sheet casting has been discussed fromthe point of view of particle–particle separation distance in theslurry. The amounts of polymer additives were optimized to givea stable, ready-to-cast slurry based on rheological measurements.Assuming that the polymers take on a sandwich configurationbetween particles poly (acrylic acid)/polyvinyl alcohol(surface/PAA/PVA/PAA/surface layers), then 9.1 nm, the calculatedsurface-to-surface separation distance (SSD) betweenparticles could be taken as the criterion to prepare crack-freesheets. Indeed, the sheets prepared from the slurries, satisfyingthe above condition, were crack free. However, for the slurrieswith less space between particles, due to the inability of PVA tobind them all, cracks were formed in the cast sheets. The agglomeratedparticles in the slurries also influenced the macroscopicbehavior of the sheets. Therefore, a well-dispersed slurrywith a large enough SSD is necessary for the preparation ofcrack-free ceramic sheets from nanosized particles.