Corrosion Behavior and Microstructure of Al-Al₂O₃ Coatings Produced by Low-Pressure Cold Spraying

In this study, low-pressure cold spraying was used to deposit Al and Al-Al₂O₃ composite powders on different substrate materials, including steel, aluminum, and magnesium alloy. Corrosion performance was evaluated by electrochemical testing in 1M NaCl electrolyte and microstructure was examined by means of SEM analysis. The results show that the corrosion potential of Al-Al₂O₃ coatings depends on the content of alumina and that its presence does not appear to accelerate dissolution and failure of passivation oxide films. The investigation also revealed that pure aluminum coatings on aluminum alloy substrates can act as sacrificial anodes, thus providing corrosion protection.