Suppression of water-soluble polymer on surface-exfoliation of gelcast green body of alumina

Gelcasting has to be performed in nitrogen to avoid surface-exfoliation of the green body prepared from gelcasting in air. This study shows that the surface-exfoliation phenomenon of green bodies gelcasted in air was suppressed via adding a proper amount of water-soluble polymer (4.4wt% polyvinylpyrrolidone (PVP), 2.8wt% polyacrylamide (PAM), 1.3wt% polyethylene glycol (PEG), 0.8wt% polyethylene oxide (PEO)) to the ceramic suspension. The influence of polymer on the surface characteristics of alumina powder in water and the rheological behavior of alumina suspension were investigated and analyzed while the flexural strength and microstructure of green bodies were highlighted.