Comparative study on the microgalvanic corrosion phenomena of WE43 alloy in Cl- / HCO3- / CO32- environments

With rare-earth elements gradually coming into view, Mg-rare earth alloys like WE43, which inherit the properties of Mg alloys as lightweight structural materials, are gradually being explored. Anomalous preferential dissolution of the second phase of Mg-rare earth alloy (WE43) in the CO32- environment was identified. Further research revealed that this anomaly was due to the anodic role of the second phase in the microgalvanic corrosion with Mg-matrix protection. The interesting thing is that the second phase as cathode role was found in the HCO3- environment, like the phenomenon in Cl- environment, and the value of pH was not the decisive fact. The different microgalvanic corrosion behavior could be attributed to the reaction between metal atoms and ions in solution. In addition, the surface film of WE43 was systematically studied in three environments and specific corrosion models were developed for each environment.