(195d) Effect of Substrate Roughness On Nano-Silica Coated Micron-Scale Particle Adhesion

Industrial and pharmaceutical particle manufacturing can include processes like particle flow, mixing, storage, fluidization, and compaction which are greatly affected by the cohesive forces of particles within powders and adhesive forces between powder particles and process surfaces. Dry coatings and fillers are sometimes added to a powder formulation to modify interaction forces by altering particle surface morphology and the chemical properties of the material in the area of contact. However, if the process surface is sufficiently rough, the effect of dry powder particle coatings on adhesion can be reduced. In this study, the adhesion of uncoated and nano-silica coated alumina particles to stainless steel substrates with different roughness regimes was measured using and atomic force microscope (AFM). Surface roughness and particle geometry were measured using an AFM and scanning electron microscope, respectively. The van der Waals force of adhesion was characterized and simulated using a predictive model.