Thermal Behavior of an Oxide Layer on Aluminum

V. S. Rudnev^a, A. E. Lysenko^a, P. M. Nedozorov^a, T. P. Yarovaya^a, and A. N. Minaev^b

^a Institute of Chemistry, Far East Division, Russian Academy of Sciences,
pr. Stoletiya Vladivostoka 159, Vladivostok, 690022 Russia

^b Kuibyshev Far East State Technical University, Vladivostok, Russia

Received June 15, 2006

Abstract — Films 16 to 17 m thick were obtained on the ^#AMg5 alloy by plasma electrolytic oxidation (PEO) in an orthophosphate–borate electrolyte. Air annealing at 250, 300, 400, and 500°C for 4 h did not affect the thickness, weight, and the elemental composition of the resulting films. The contact angle for water changed from 75° to zero. In a temperature range from 250 to 300°C, the content of the crystalline -Al₂O₃ phase jumped. Above 300C, the film surface cracked and became less resistant to corrosion. PACS numbers: 68.35.Ct