Wettability by Water and Oxidation Resistance of Alumina-Coated Graphite Powder

Abstract

Graphite powder was coated with a chelate compound of aluminum and heated at 500°C in air to prepare Al₂O₃-coated graphite powder. The sedimentation volume and the heat of immersion in water indicated that the wettability of the graphite powder by water was improved by the Al₂O₃ coating. The oxidation resistance of Al₂O₃-coated powder was higher than that of the uncoated one. The first and second adsorption isotherms of water vapor indicated that H₂O vapor was adsorbed not only physically but also chemically on the Al₂O₃-coated layer. The specific surface area by N₂ and the second adsorption isotherms of water vapor suggest that the layer has micro pores<0.4nm in diameter.