RESUMO
The pitting corrosion resistance of the aluminum alloy has been achieved by a simple preheating treatment. Different techniques were used: potentiodynamic polarization, weight loss, thermometric and examination of the surface by scanning microscope. The proposed procedure composed of two processes, the first one was to expose the surface of metal to heated distilled water at 100C for 60-120 min. The same effect was realized by exposure of the metal to superheated steam. The second procedure was the exposure of the aluminum to a hot solution of inhibitor for 5 minutes. The role of the first step was to modify the chemical composition and thickness of the protecting film on the metal surface. The film thickness was found to increase by time of treatment. Less hydrated aluminium hydroxide exhibited the best chemical resistance [Boehmite, Gibbsite]. The role of inhibitor in the second process was played by preventing hydration of the produced surface film which initiated the pitting corrosion. The nature of the last method was found dependent on the type of inhibitor used