ABSTRACT
Control of the rheological behavior and stability of concentrated dispersions that are widely used as coatings, clays and ceramics, electronic pastes, paints, pharma ceuticals, sludges, and effluents is critical for the successful manufacturing of high-quality products of particulate suspensions. As industry moves toward higher solids loading to improve the material properties, control of the basic rheological behavior and physical stability of suspensions has become increas
ingly important. To achieve optimal process conditions, a basic understanding of the role of different variables that govern the suspension properties, such as particle size, particle size distribution, particle shape, volume fraction of the parti cles, temperature, shear rate, aging, use of polymers, and colloidal forces on flow properties of suspensions is required [1,2]. The effect of interparticle forces on suspension properties becomes increasingly important as the particle size is de creased. The range of interparticle interactions is of significant importance in terms of stability, flow properties, and packing of submicrometer-sized particles. In order to improve the material properties to minimize the inhomogeneities in the packing of particles and the distribution of the pores, interparticle forces in the suspension need to be manipulated during processing and forming [1,3,4]. The effect of nonhydrodynamic interactions between suspended particles on the behavior of the dispersion becomes more important at a higher volume fraction of the particles as the average interparticle spacing decreases [5]. Due to an in crease in surface-surface separation at low volume fractions, the particle-particle interactions become less pronounced and the rheological properties of dilute sus pensions are mainly affected by hydrodynamic forces and Brownian motion of the particles [6].
