Fabricating an anti-corrosion carbonate coating on Mg-Li alloy by low-temperature plasma

Despite the huge demand for ultra-light magnesium-lithium (Mg-Li) alloys, practical applications of Mg-Li alloys are still severely restricted due to their poor corrosion resistance. Here, we report a new method utilizing low-temperature plasma to grow an oxide layer on the Mg-Li alloys in atmospheric condition, which reacts with CO2 and water in the air and consequently transform into a protective coating. The prepared coating has a layered structure consisting of a Mg(OH)(2) inner layer and a Li2CO3 outer layer. The composition distribution can be attributed to the different migration rates between Li+ and Mg2+ during coating formation. The Li2CO3 outer layer is sufficiently compact and very stable, with an ultra-low solubility in water, explaining the superior corrosion resistance of the coating in 3.5% NaCl solution. This simple and eco-friendly surface treatment provides a novel way of fabricating protective coatings on Mg-Li alloys.

Automated summary

This study presents a new method to grow an oxide layer on Mg-Li alloys using low-temperature plasma, which reacts with CO2 and water in the air to form a protective coating. The prepared coating has a layered structure and exhibits excellent corrosion resistance for Mg-Li alloys.