Polysaccharides are commonly used as binders in metal oxide colloidal processing. However, if the macromolecular chains are able to adsorb on ceramic particles surface, the suspension deflocculating properties are also favored. This paper investigated the use of dextrin as a bio-dispersant on structural and morphological properties of Al2O3 materials. The interaction mechanism between dextrin and Al2O3 surface and the additive efficiency of producing less agglomerated systems were discussed. The suspensions behavior was pH-dependent, being the pH 6 the best condition for obtaining more compact systems in dextrin presence. The first monolayer saturation of the Al2O3 active sites occurred at 1.5 wt. % of dextrin and a second adsorption layer started above this additive concentration. The highest percentage of densification was 96.25% for the suspension containing 30 vol. % solids and 1 wt. % dextrin. The presence of dextrin also influenced the microstructure of the systems, providing a better bridging between Al2O3 particles. The use of dextrin at low dosages proved to be efficient in the stabilization of aqueous alumina suspensions.

Keywords: Dextrin, α-Al2O3, Dispersant, Adsorption, Ceramic suspension