Influence of heat treatment on corrosion behavior of hot rolled Mg5Gd alloys

The influence of heat treatment on the corrosion behavior of rolled Mg5Gd alloys in 3.5 wt.% NaCl solution saturated with Mg(OH)(2) was characterized by immersion test, electrochemical test, scanning electrochemical microscopy (SECM) and corrosion morphology analysis in order to improve the corrosion resistance of Mg alloys. The results showed that solution treatment reduced the corrosion rate of the Mg5Gd significantly, resulting in relatively uniform corrosion and shallow corrosion cavities due to the dissolution of Cd-containing particles. The following aging process could further decrease the corrosion rate. Precipitation of nano-sized Cd-containing particles did not cause apparent micro-galvanic corrosion, which could be attributed to the formation of a protective corrosion product film fully covering the particles.

Automated summary

Heat treatment significantly reduces the corrosion rate of Mg5Gd alloys, resulting in more uniform and shallow corrosion, and the precipitation of nano-sized Cd-containing particles does not cause apparent micro-galvanic corrosion.