Fabrication of transparent yttria ceramics by alcoholic slip-casting

Y2O3 transparent ceramics were prepared from alcoholic slurries of Y2O3 nanopowders via a slip-casting method to avoid the hydrolysis issue. Polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG) and polyethylenimine (PEI) were used as dispersants to improve the rheological properties of the slurries. It was found that PEI is the most effective dispersant in ethanol. The adsorbed amount of PEI was evaluated by infrared absorption and rheology measurements. Y2O3 slurry with a solid loading of 20.8 vol% and a viscosity of < 0.1 Pa s at the shear rate of 10 s(-1) was obtained using 1.5 wt% PEI. The slurry yielded a homogeneous green body, and finally resulted in a high-quality Y2O3 ceramic with the in-line transmittance of 80% at 800 nm.