engleski

Passivity of sputter deposited Al-alloys

Aluminum alloys are widely used because of their low density, high specific strength, and good resistance to uniform corrosion. Aluminum, being an inherently active metal, owes its stability to a protective oxide film. A major corrosion issue with aluminum is the localized breakdown of the passive film, which leads to the initiation and growth of corrosion pits in chloride-containing environments. Improvements in the localized corrosion resistance of aluminum by conventional alloying techniques (equilibrium ingot metallurgy methods) are limited for two reasons: (i) the resulting intermetallic phases can be detrimental to corrosion resistance, (ii) most alloying elements which are known to impart improved corrosion properties have a limited solubility in aluminum. The passivity and corrosion behaviour of several supersaturated Al-Mo alloys formed by cosputter deposition have been investigated. The passive film that forms on each alloy becomes enriched in oxidized alloying component during anodic polarization. Sputter deposited Al-Mo alloys exhibit enhanced passivity and resistance to passivity breakdown in comparison with pure metal components. Many of the proposed passivity mechanisms such as vacancy-solute complex formation, pHpzc, structure stabilization, etc, are discussed.

Al-Mo alloys; sputter deposition; passivity

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