The effects of solids loading and dispersion order on the state of aqueous slips of either zirconia or alumina, and binary slips of these two powders, have been examined. Since these powders can acquire surface charge when they are dispersed in aqueous media, changes in the ionic composition of the slip can occur as a result of the addition of solids. At higher solids loading, a substantial fraction of the ionic activity within the slip may be attributed to the solid itself. As the solids loading within unary powder suspensions is increased, it is possible to drive the suspension pH toward the point of zero-charge for the powder, resulting in diminished electrostatic stabilization and possible powder agglomeration. An analytical model was constructed to account for the observed results. This embodied a simple surface site complexation model which was augmented to include material and charge balance constraints on ionized surface sites as well as solvated ions. For binary powder dispersions of alumina and zirconia, it was found that the order of dispersing the two components could have a pronounced effect on the overall suspension behavior. The variability in results is attributed to the solubility of the alumina in the basic processing media.

Laser anemometry enables the measurement of complex flow fields via the light scattered from small particles entrained in the flow.

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