Abstract
Dispersions of ceramics show physical and chemical properties strongly influenced by surface interactions between particles and liquid. As a strategy to reduce environmental impacts, ceramic dispersions are becoming more concentrated, resulting in complex systems and more susceptible to surface interactions. Characterizing the wettability of the particles by liquid is an effective way to determine the effect of surface interactions. Wettability is the tendency of a liquid to spread over a solid, described as contact angle. The modified Washburn method is recommended for powders, based on the capillary rise of the liquid into a packed bed of powder inside a tube. In this work, the objective is to measure the contact angle of calcium carbonate with two particle size distributions, for evaluating the applicability of the modified method of Washburn to contact angle measurements of ceramic powders. The contact angle measurements of calcium carbonate using simplified apparatus were adequate and sensitive to particle size distribution, sample preparation and porosity of the system. The lower the porosity of the system, the lower the calculated contact angles. However, the variation of calculated and literature values suggests that contact angles calculated by the modified Washburn method are comparative, once the same sample configuration and preparation are maintained.
Keywords:
wettability; contact angle; calcium carbonate; modified Washburn method
