Effect mechanism of ultrasound on growth of micro-arc oxidation coatings on A96061 aluminum alloy

• Effect mechanism of ultrasonic vibration on MAO is explored.
• Micro-flaws induced by ultrasound are helpful for healthy growth of MAO coating.
• The flaws induced by ultrasound experience a dynamic development.
• Ultrasound assisted MAO improves the vibration-resistance of MAO coatings.

Ultrasound vibration was introduced during and after MAO process of A96061 aluminum alloy to investigate the effect mechanism of ultrasonic action on the growth of MAO coatings. The results show that during the MAO process ultrasound improved the growth behavior and the vibration-resistance performance of MAO coatings, while ultrasound post-treatment greatly increased the number of micro-flaws in the coatings and decreased the corrosion resistance of the coatings. Producing-healing circulation of micro-flaws caused by ultrasonic vibration during PEO process was thought to be the mechanism of ultrasonic action on coating growth.