The effect of the nanometric-ranged particle size of the starting powder through a simple and well-established shaping method, slip casting, has
been studied. Several alumina suspensions with the same viscosity (but different solid content suspensions) and different particle size (11, 44,
190 and 600 nm) were prepared and shaped into a dense body. The green and sintered densities ranged between 30–67% and 63–99% of the
theoretical value, respectively. These values, together with the microstructure observations reveal the effect of the solid content of the suspensions
and the characteristics of the ceramic powder, leading to the determination of an optimal particle size. Based on both processability (rheological
behaviour) and microstructure (density and grain size) it has been determined that particles with sizes ranging 100–300 nm are the best for preparing
concentrated suspensions with low viscosity and bodies with density close to the theoretical value when using conventional pressureless sintering
densification.