유기용매를 이용한 CeO2가 코팅된 알루미늄 양극산화막 표면에 빠른 소수성 구현 및 내식성에 대한 연구

Abstract

Rare-earth oxides, which provide favorable sites for adsorption of hydrocarbons in ambient, are well-known to shows an intrinsic hydrophobicity. Such rare-earth oxides are chemically stable at high temperature and under UV irradiation, so that the coating with rare-earth oxides is considered to be a promising alternative for hydrocarbon or fluorocarbon-based materials for realization of hydrophobicity. However, the adsorption of hydrophobic hydrocarbon molecules is dependent on the ambient condition, thus the hydrophobicity of rare-earth oxide surface cannot show reliable reproductivity. To solve such limitations, we introduce a new method to realize hydrophobicity on rare-earth oxide by immersing the oxide in immiscible solvents (e.g., hexane and toluene). The immersion of cerium oxide coated surface in immiscible solvents significantly promotes the adsorption of hydrocarbons, so that the surface shows hydrophobicity less than 24 hours. In addition, the hydrocarbon on cerium oxide can be removed at high temperature, but the hydrophobicity can be also recovered by immersing in immiscible solvents. Therefore, if the surface of cerium oxide layer exists on the surface, the desorbed hydrocarbons on the cerium oxide layer can be restored by immersing in hexane or toluene. Due to the adsorption of hydrocarbons on cerium oxide layer, the anodic oxide surface with cerium oxide coating shows hydrophobicity so that the surface is not wetted well. Therefore, the corrosion resistance can be also improved.