The behaviour of the atmospheric corrosion of galvanised steel is evaluated in three cities in Chile and Mexico. Meteorological variables were measured (T, RH, rainfall, wind speed) along with the principal air pollutants (SO2 and Cl- ions). Comparing the data from the Chilean and Mexican weather stations, there is a clear trend of decreased corrosion with the increase in mean temperature, and statistically significant influence from air pollutants was not seen under the conditions in question. The corrosion process does not develop uniformly, with the formation of voluminous corrosion products distributed heterogeneously over the galvanised surface. The main corrosion products in both environments, identified by XRD analysis, are: Zincite (ZnO), Zinc Hydroxide Sulphate Hydrate (Zn(OH)2)3(ZnSO4)(H2O)5), Zinc Oxide Sulphate Hydrate (Zn4O3(SO4).7H2O), Zinc Sulphate Hydroxide Hydrate (Zn4SO4(OH)6.4H2 O) and Simonkolleite (Zn5(OH)8Cl2.H2O). The presence of sulphate in the corrosion products shows that sulphur dioxide pollution plays an importance role in galvanised-steel corrosion, though no statistical evidence was found.
|Number of pages||20|
|Journal||International Journal of Electrochemical Science|
|State||Published - 2015|
- Atmospheric corrosion
- Metal coatings