Stabilization of Silicon Carbide Whisker Suspensions: I, Influence of Surface Oxidation in Aqueous Suspensions

The extent of surface oxidation controls the stability of silicon carbide aqueous suspensions. In the present study, x-ray photon spectroscopy (XPS) was used to determine the extent of oxygen on as-received and oxidized silicon carbide whiskers. The isoelectric points at pH 6.0 and pH 4.0 for the as-received and oxidized whiskers, respectively, correlated with the XPS analyses, indicating essentially a silica surface on the oxidized whiskers and both Si-O and Si-C bonds on the surface of the as-received whiskers. Suggestions are made regarding the utility of the oxidation treatment in processing whisker-reinforced ceramics.