The Effect of Water-Soluble Salt Contamination on Coating Performance

Abstract

This paper summarizes the results from laboratory investigations of water-soluble salts effect on protective coatings’ performance. The test program has included assessment of both sodium chlorides’ and iron sulphates’ influence on cathodic disbonding (ASTM G8), ageing resistance under cyclic climatic conditions (STD 1027), and blistering when immersed in distilled water (ISO 2812/2).  Two commercially available epoxy systems and an epoxy clear lacquer were included in the tests.

Salt contaminations had little or no effect on scribe creep during the cyclic test. For all other test parameters, there were significant reductions in the coatings’ performance as the salt concentrations increased. 

KEY WORDS: adhesion, blistering, cathodic disbonding, scribe creep, underfilm corrosion