What Does Soluble Salt Contaminant Mean?
Soluble salt contaminants are inorganic substances that are soluble in water. The major soluble salts that cause the most damage to coatings and base materials are chlorides, nitrates and sulfates.
A soluble salt contaminant in between a coating and a base material causes soluble salt contamination and can cause subsequent material failure through a variety of means.
Corrosionpedia Explains Soluble Salt Contaminant
Soluble salt contamination can be detrimental to a coating due to a process called blistering, which occurs when a soluble salt trapped beneath the coating draws water through the coating. Over time the water creates pressure and causes the coating to have an appearance similar to a blister. This process can cause portions of the coating to eventually break off, leaving an unprotected base material.
Soluble salt contamination can also have an undesirable effect on the base material itself. When water is drawn in by soluble salts it forms a saline solution that changes the electrical potential of some areas of the base material and promotes oxidation. Furthermore, saline solutions are often acidic and can further degrade the base material.