Corrosion Resistant Coatings Overview

Industrial Coating Processes and Design

Corrosion resistance coatings are available for most materials, surface types, and application environments. Corrosion resistant coatings can significantly increase the usable lifetime of materials while reducing maintenance and replacement costs. There are many possible operating applications which will result in corrosion. The following are many types of common corrosions which occur in applications;

Galvanic corrosion is one of the most common forms of corrosions which does occur in products. There are three conditions that must exist for galvanic corrosion to occur. First there must be two electrochemically dissimilar metals present. Second, there must be an electrically conductive path between the two metals. And third, there must be a conductive path for the metal ions to move from the more anodic metal to the more cathodic metal. Corrosion resistant coatings would be applied to eliminate one or more of the corrosion causing conditions.

Caustic agent corrosion is caused by corrosive impurities in gases, liquids, solids or any combination of the three, which come in contact with a material. Most petrochemical process gases contain a certain amount of impurities, which may dissolve into the water and become corrosive. For example, hydrogen sulfide is a common impurity in cracked gas. Usually these impurities are not corrosive in a dry condition, but when moisture is present, they will dissolve into the water and form hazardous acidic vapor or droplets. With these conditions present in the petrochemical process, applying corrosion resistant coatings is imperative