Studies On Oxidation Behavior And Properties Of Surface Oxide Film Of Aluminum In High-Temperature Water Vapor

Oxide films formed on aluminum surface in high-temperature water vapor were studied in this paper. The kinetic model and the oxidation behavior of aluminum in high-temperature water vapor were investigated with the method of X-ray difrraction(XRD) energy dispersive spectroscopy(EDS) and scanning electron microscopy(SEM). The corrosion-resistant property of oxide film on aluminum surface was also studied by salt-sprayed experiment.The research results showed that aluminum can be oxided in high-temperature water vapor. The water vapor molecules were absorbed and dissolved into the aluminum, and then caused the reaction on solid-gas interface. Water vapor molecules were decomposed, generating hydrogen. Oxygen ion and aluminum ion could diffuse each other in oxide films. The thickness of oxide films increased with the prolonging of oxidation time and the upgrading of oxidation temperature. The oxide films are composed of A12O3.3H2O (Gibbsite) and A1O(OH) (Boehmite) at l40℃ for 24h. The oxide films are composed of AlO(OH) (Boehmite) at 200℃ for8h 12h 24h 48h, 72h or at 250℃ 280℃ 300℃ for 24h. The oxidation products are composed of A1O(OH) (Boehmite) AlO(OH) (Diaspore) 和 α-Al2O3(Trigonal) at 350℃ for 24h. The oxide films that formed at 200℃ for 8h, 12h 24h 48h 72h or at 250℃ 280℃ 300℃ for 24h have good corrosion-resistant property.