Polyelectrolyte mediated interaction of alumina in wet jet milled slurry/ball milled slurry supernatants

Abstract

In a recent paper by Omura et al.,1) wet jet milled α-alumina slurries exhibited distinctly different stability behavior compared to ball milled ones in terms of re-flocculation efficiency, rheological properties and packing density. The distinction was attributed to the different behavior of the same NH4+ salt of poly (acrylic acid) in the two milling methods used. Force measurement via colloid probe method in the centrifuged supernatant of the milled slurries confirmed that the interaction distance between an alumina colloid probe and sapphire surface is about two times larger in wet jet milled slurry supernatant compared to the just ball milled one. This result confirmed that processing variables do affect the polyelectrolyte behavior in the slurry. The net force was always repulsive on approach in either supernatants.