Effect of laser surface melting and coatings on corrosion performance of Mg alloy

Magnesium alloys owing to their ultra light weight, high specific strength, high damping capacity, excellent machinability and good castability are finding tremendous potential applications in automotive, aerospace and defence. However, Mg and its alloys are highly susceptible to corrosion, which undermine their safe usage for structural applications. In light of this there is a thrust towards developing these materials for improved corrosion resistance and thereby provide extended service life. In the present work we demonstrate a laser based surface modification technique to improve the corrosion resistance of these alloys. Here a highly intense laser beam is used to directly melt the surface of the Mg alloy and modify the microstructure. The effect of these changes in microstructure on the corrosion behaviour of these alloys constitutes the first part of the study. In another attempt, coatings of aluminium and chromium are developed on the surface of Mg alloys by direct laser melting technique. The effect of these coatings on the corrosion resistance of the Mg alloy is investigated in the second part of our study.