The hydrodynamic properties of surface treated powders were investigated using the FT4 Powder Rheometer (R) through aeration studies. Powders of varying Sautermean diameterwere selected to reveal the effect of intrinsic cohesion on the ability to fluidize the powder. The studies were used to explore the following concepts: (1) repeatability of the measurements, (2) ability to discern powder columnexpansion, (3) estimation of the minimum fluidization velocity based on pressure drops, and (4) evaluation of the various stages of fluidization. Surface treatment showed significant improvement and uniform, particulate fluidization for the larger particle sizes. Estimations ofminimumfluidization velocity in an agitated environmentwere deduced from pressure drop curves and showed significant differences for the smaller particles sizes, however converged towards the theoretical value for the larger particle sizes. The various stages of powder column fluidization fromfixed bed to entrainment were also evident through experimentally determined bed expansion curves. (C) 2020 Elsevier B.V. All rights reserved.