Abstract: The rheological behavior of the slurry of 95 alumina ceramics for gelcasting was discussed in this paper. The effects of pH value, dispersants and ball milling time on the viscosity of slurry were analyzed. Al_2O_3 slurry with 58vol; solid volume loading and 110 mPa·s viscosity was prepared by the orthogonal test of L_9(3~4). Aiming at the inhibition of surface oxygen on polymerization especially, the surface-exfoliation was overcome by coating on the surface of mold, which neither increases the organic binder content of the green body nor decreases the strength of the green body. The results indicate that the green properties of 95; alumina ceramics prepared by gelcasting was better than one by hot injection moulding.

Key words: The rheological behavior of the slurry of 95 alumina ceramics for gelcasting was discussed in this paper. The effects of pH value, dispersants and ball milling time on the viscosity of slurry were analyzed. Al_2O_3 slurry with 58vol; solid volume loading and 110 mPa·s viscosity was prepared by the orthogonal test of L_9(3~4). Aiming at the inhibition of surface oxygen on polymerization especially, the surface-exfoliation was overcome by coating on the surface of mold, which neither increases the organic binder content of the green body nor decreases the strength of the green body. The results indicate that the green properties of 95; alumina ceramics prepared by gelcasting was better than one by hot injection moulding.