Corrosion product formation on zinc-coated steel in wet supercritical carbon dioxide

In a wet supercritical carbon dioxide atmosphere, carbon dioxide is dissolved into water and causes corrosion of zinc-coated steel. The first corrosion products appeared in singular nano scale initiation sites, which gradually grew in number and size and ultimately covered the whole surface. Zinc hydroxy carbonate was detected as a rapidly forming needle-like corrosion product, which prevailed at short exposure times (from minutes to hours). A prolonged exposure caused conversion of zinc hydroxy carbonate to anhydrous zinc carbonate with high crystallinity and a stable, dense layer was formed on zinc. The chemical transition from zinc hydroxy carbonate to anhydrous carbonate was reported for the first time and is in the light of current literature unique for wet scCO(2) atmosphere. (C) 2021 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.

Automated summary

In a wet supercritical carbon dioxide atmosphere, corrosion of zinc-coated steel occurs as carbon dioxide is dissolved into water. The corrosion products initially appear in nano scale initiation sites, gradually increasing in number and size until they cover the entire surface. Zinc hydroxy carbonate is rapidly formed as a needle-like corrosion product in short exposure times, while prolonged exposure leads to the formation of anhydrous zinc carbonate, creating a stable and dense layer on the zinc surface. This chemical transition from zinc hydroxy carbonate to anhydrous carbonate is reported for the first time in wet supercritical carbon dioxide atmosphere.