Corrosion can be a big problem for parts and machinery operating in marine environments. Mild steel is commonly used for marine applications due to its strength, ease of fabrication and relatively cheap price.
The only problem is, it corrodes very easily when exposed to seawater. So when mild steel isn’t protected by a corrosion resistant layer or barrier, it quickly loses its strength and can, therefore, result in failure of parts.
What is Corrosion?
Corrosion is the gradual destruction of materials by chemical reaction with their environment. It is the oxidisation of the metal at the interface between the metal and the environment, and the reaction results in the degradation of the mechanical properties of the metal. Corrosion is dependent on many factors, including oxygen concentration, pH, water temperature and the presence of dissolved salts such as chloride, sulphate and sulphites.
Pitting corrosion is a type of corrosion that occurs on mild steel in a localised fashion. The steel penetration can be very deep in relation to the area under attack, and it is therefore one of the most dangerous types of corrosion.
Bacterial corrosion can also be referred to as micro-biological corrosion or anaerobic (without oxygen) corrosion. This type of corrosion is likely to happen if the environment that the metal is exposed to supports bacterial activity. For bacterial corrosion to occur, there must be stagnant water, a hydrocarbon food source e.g. oil or coatings, the presence of sulphates, an operating temperature of between 20 – 40C, and the presence of bacteria.
Corrosion Prevention Using Metal Coatings
The prevention of corrosion requires the elimination or suppression of the chemical reaction between the environment and the metal. One way of preventing this reaction is by applying a metal coating to the surface of the substrate, and the effectiveness of the coating depends on factors including the type of coating used, the operating environment and the coating type.
SeaTEC 100 Marine Corrosion Protection
Here at NiTEC, we have developed a corrosion resistant metal coating that effectively protects mild steel from salt spray corrosion and marine corrosion for an extensive period of time. For more information about SeaTEC 100 and its ability to extend the life of parts exposed to subsea conditions, please contact the expert team at NiTEC by calling 0845 224 3571 or email us at email@example.com.