The degradation mechanism of an epoxy-phenolic can coating

Paint remains a widely employed approach to corrosion control due to its relatively low cost and proven efficacy. Nonetheless, the processes governing long-term deterioration of intact organic coatings (in the absence of defects) are not fully understood. In this contribution, we investigate the degradation mechanism of a corrosion resistant epoxy-phenolic can coating. In-situ time-resolved ATR FTIR is applied to monitor both the chemical integrity of the coating and water uptake as a function of immersion time in deionised water or electrolyte. Ion transport is then assessed across free standing films, and the morphological changes accompanying immersion are examined using ex-situ advanced scanning probe microscopy techniques. Coatings are found to deform as a result of water sorption during immersion in electrolyte or water, yielding regions of a heterogeneously hygroscopic nature, yet no change in functional group chemistry is found to occur. (C) 2016 Elsevier B.V. All rights reserved.