Effects of particle dispersion on the properties of suspension-sprayed coatings

Abstract

Suspension spraying is a promising surface modification technique, because finer particles can be used in contrast to the case of conventional thermal spraying. However, the optimal conditions for preparing suitable suspensions have not yet been established. Thus, the effects of particle dispersion and flocculation states on the properties of suspension-sprayed coatings were examined in the present study. Y2O3 suspensions were prepared using various quantities of the dispersant. The flow curves and gravitational settling behaviors of the prepared suspensions were investigated. The amounts of the dispersant adsorbed on the particles were also determined. In addition, Y2O3 coatings were fabricated using suspension spraying, and the properties of the obtained coatings were investigated. The addition of the dispersant affected the suspension flow characteristics, because the amount of the dispersant adsorbed increased with increasing dispersant concentration. Furthermore, the coating characteristics improved as the apparent viscosity of the suspension decreased.