Characterization of dispersion and coagulation behaviour of alumina and silica particles in the mixed slurry by a drain time measurement

Abstract

In this study, we have proposed "drain time" (DT) measurement to be used for the characterization of particle dispersion states in the multi-component slurry, which are much more complicated than those in single-component one. The DT is related to drainage characteristics of a solvent from ceramic slurry cake, of which particle packing is correlated in principle to particle dispersibility in the slurry. For mixed slurry of alumina and silica powders, higher DT values at acidic and basic conditions indicated relative good dispersion but lower DT values around neutral pH region implied hetero-coagulation of alumina and silica particles. These dispersion and coagulation patterns were confirmed by electron microscopy for thin section of in-situ solidified slurry, and hence the DT measurement was found to be feasible for the characterization of particle dispersibility in multi-component slurry.