Hydrophobic coagulation of alumina slurries

This study reports a new wet forming method by hydrophobic modification of short-chain anionic dispersants. The influence of the content and type of hydrophobic chains on the rheology of alumina slurries, the drying shrinkage rates of wet bodies, the density and strength of the green bodies, and the density and microstructure of the resultant ceramics were intensively investigated. It is revealed that hydrophobic modification can endow short-chain dispersants with coagulation ability, when 0.3 wt% short-chain PIBM (a copolymer of isobutylene and maleic anhydride) was combined with 0.1 wt% TMAC (tetramethylammonium chloride), solid loading of the slurry was increased to 58 vol% and the slurry can coagulate to a wet green body in a short time. The resultant green body showed a uniform microstructure and was successfully sintered into translucent ceramics.