Zinc Corrosion in a Crevice

C. Taxén, and D. Persson
Swerea-Kimab, Stockholm, Sweden

Corrosion of metals in confined zones is a big industrial problem. The electrochemistry of such localized corrosion processes is complicated by the impact of the corrosion processes on the composition of the local solution.

In the present problem, local interaction with the atmosphere causes uptake of O2 and CO2 and evaporation of water from the initially dilute NaCl-solution. This model describes the local aqueous equilibria and the transport processes coupled to corrosion reactions at a zinc metal surface.

The model describes the amount of corrosion products deposited in the crevice well, and the specific compounds as well as their location in the crevices agree with observations. The results are detailed and allow for assessment of the importance of the various complex forming reactions.