Evaluating the corrosion under insulation

A recent study focuses on the evaluation of epoxy-based coating degradation under thermal insulation at elevated temperatures on different steel substrates.

A corroded spot on a white painted surface.
Epoxy-based coatings are conventionally used for protection against CUI due to their superior mechanical and chemical properties that determine the extended overall lifespan of a coating Image source: Blende 11 - stock.adbobe.com (symbol image).

Corrosion under insulation (CUI) remains one of the most critical issues in the petrochemical industry. Organic coatings exposed to high operating temperatures and thermal cycling conditions are susceptible to failure and thus require coating performance evaluations under representative thermal insulation conditions. A new study presents experimental designs to investigate the degradation of an organic polyamine-cured epoxy coating under accelerated laboratory test conditions.

Predicting coatings’ service lifetime

The results showed that polyamine-based epoxy coating experienced thermal degradation starting at temperatures above 130 °C under mineral wool insulation in accelerated and cyclic CUI tests. Chemical degradation was the primary mode of degradation, with the formation of carbonyl functional groups and increased glass transition temperature observed at higher exposure temperatures. The proposed combination of electrochemical, spectroscopic, mechanical, and microscopy techniques allows quantifying coating performance under insulation and subsequently provides insights into predicting coatings’ service lifetime.

The study has been published in Progress in Organic Coatings, Volume 180, July 2023.

Event tip

Protective coatings are also in the focus of the EC Conference Protective & Fire-retardant Coatings on October 18 -19 in Berlin, Germany. The latest developments in protective and fire-retardant coatings will be presented to you in one conference.

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