Assessment of the Surface Free Energy of Aluminum Powders

The surface free energy of powders is an important thermodynamic characteristic that determines their physical properties and provides the possibility to predict the formation of given structural and morphological properties. The work presents the results of a comparative study of the surface free energy (SFE) of two aluminum-containing powder systems: the initial aluminum powder (ASD-4), which consists of spherical particles, and an aluminum–activated carbon–graphite composite powder with plate-shaped particles and a significantly more developed surface. The difficulties encountered in measuring contact angles for powder systems to determine the SFE values lead to the search for methods to avoid these problems. In this regard, the dispersion component of the surface energy of aluminum-containing powders was estimated using the capillary elevation method based on a theoretical approach using the modified Washburn equation and the Fowkes adhesion formula. The results of the experiments showed a significant increase in the dispersion component of the SFE for the aluminum–activated carbon–graphite composite powder with an extremely developed surface compared to the initial ASD-4 aluminum.