Aspects on Early-Stage Corrosion of Different Zinc Alloys: Wet scCO2-Induced Corrosion

The surface activity of different zinc alloys was evaluated in wet scCO(2). The zinc coating surface chemistry governed the corrosion product formation. On zinc and Zn-Al coatings, the Al2O3 layer prevented growth of corrosion products. A Zn-Al-Mg coating showed high initial reactivity due to active Zn-Mg phases. An electrogalvanized coating was very active due to a high ratio of exposed, less dense planes. In a Zn-Fe coating, several Zn-Fe phases were susceptible to wet scCO(2) at the same time, triggering the sacrificial effect of Zn. Wet scCO(2) is a convenient medium to assess the early-stage corrosion of metal coatings.

Automated summary

The surface activity of different zinc alloys in wet supercritical CO2 was evaluated, with the surface chemistry of the zinc coating governing corrosion product formation. The behavior of different coatings varied in wet supercritical CO2, with some preventing growth of corrosion products while others showed high reactivity. Wet supercritical CO2 was found to be a convenient medium for assessing the early-stage corrosion of metal coatings.