The Influence of the External Salinity in the Osmotic Blistering on Marine Coatings in Total Immersion

Abstract

The use of anticorrosive paints to protect the hulls of ships is essential. These coatings are deteriorating because they are completely submerged. One phenomenon that appears in the degradation of the coating is blistering.This type of blistering has two origins, the cathode and osmotic.The cathodic blistering occurs as a result of the cathodic reaction of corrosion process, that takes place on the metallic substrate. The osmotic blistering is caused by the difference of concentration of the solutions (pollution solution interface and external). Applying these coatings on nonmetallic substrates would result in blistering, therefore, of osmotic origin. This article presents a study in plastic surfaces painted with chlorinated rubber pigmented with iron oxide. These were contaminated with NaCl at the interface substrate / paint and immersed in water with different (salt concentrations) salinities in order to recreate the various salinities of sea water which can be exposed the ship’s hull.
The objective of this work is to analyze the influence of external salinity on the emergence of such blistering.