The surface chemistry differences between two alumina powders is shown to have a significant effect on the properties of concentrated aqueous dispersions of the powders. The initial dispersion pH and magnitude and sign of the initial mobility of the particles (determined by acoustophoresis) are different for the two powders because of differences in surface impurity contents. As a result, the two powders require different amounts of dispersant to achieve stability in dispersions near their isoelectric points. The surface chemistry differences between these two aluminas illustrate the importance of examining ceramic dispersion properties at the concentrations used in processing the material. [

ChemInform Abstract It is shown that the initial dispersion pH and the magnitude and sign of the initial mobility (zeta potential) of the dispersion are strongly influenced by the surface chemistry of ceramic powders. As a result, alumina powders with differences in their surface chemistry require different amounts of dispersant to achieve stability in dispersions near their isoelectric points.