The effect of surface finishing and aluminium thin film coating on corrosion behaviour of AZ31 alloy

Magnesium alloys, possessing suitable properties for application in automobile and aerospace industry,are highly susceptible to corrosion, in specific, wet corrosion. Therefore, corrosion behaviour of the magnesium alloy AZ31 was undertaken in this study. The effect of the surface finishing and thin film coating on corrosion behaviour of AZ31 alloy is reported. Using thermal evaporation method, the AZ31 alloy was coated with aluminium of thickness 50 nm at different surface finishing features.The SEM micrograph of the surface showed a uniform coating of the aluminium on the surface of AZ31. Potentiodynamic polarization profiles obtained for the alloy were used for understanding the corrosion behaviour. The improvement of corrosion inhibition with proper polishing and thin film coating of aluminium was observed on AZ31 alloy, which is discussed in this paper.