Abstract
Hard metals are commonly produced following a powder metallurgy route, which involves powder production, mixing, granulation, pressing and sintering. Granulation is commonly done by spray-drying. A polymeric binder is added to the suspension prior to spray-drying to impart a sufficient strength to the granules. The amount of binder will largely affect granule properties such as granule strength, density, and friction behaviour and thus the pressing of the powder body. In this presentation, we will present results on direct measurements friction and adhesion of the granules using the atomic force microscope (AFM). Measurements can easily be performed between two single granules or a granule and a flat substrate. We will describe how the granule friction and adhesion varies with binder content, applied load and relative humidity. The results will be related to the binder distribution in the granules.
