Development of a Powder Wettability Evaluation Technique by Analyzing the Increase in Internal Pressure due to Capillary Suction of Closed Powder Bed —Effect of Powder-Bed-Preparation Method and Powder Surface Area Estimation Method—

Abstract

Evaluation of powder wettability is important to prepare well dispersed slurries. Therefore, in this study, a technique for evaluating powder wettability was developed to analyze the increase in the internal pressure of a closed powder bed due to capillary suction to determine the contact angle of the powder. The effect of the powder-bed-preparation method and powder surface area estimation method on the determined value of the contact angle was discussed. We demonstrated that the improved air permeation test proposed in this research can accurately determine the powder surface area, resulting in a faithful determination of the contact angle of the powder. It was also shown that compression under the shearing method could result in a denser and more homogeneous powder bed when compared to the conventional tapping method, indicating high reproducibility for estimating the contact angle.