What Does Protective Coating Mean?
A protective coating is a layer of material that is applied to a substrate to prevent it from being damaged by environmental factors such as corrosion, abrasion and weathering. They do this by either blocking external environments from coming together to start the corrosion process, preventing the electrochemical reaction from occurring or routing the corrosion process in a direction that will not harm the asset.
Protective coatings can be made from a variety of materials, including polymers, ceramics, metals and composites, and are commonly used in industries such as automotive, aerospace, marine and construction.
Corrosionpedia Explains Protective Coating
Corrosion, the gradual deterioration of materials due to chemical reactions with their environment, is a major concern for many industries that deal with metal structures and components because it lead to the failure of critical components and structures. Protective coatings are commonly used to prevent corrosion, and there are several types of coatings that can be used depending on the specific application.
Common types of coatings include:
- Barrier coatings.
- Sacrificial coatings.
- Anti-fouling coatings.
Barrier coatings are layers of material that physically separate the metal substrate from its environment. This type of coating is typically made from polymers or ceramics and is applied in a thin layer to the metal surface. The barrier coating prevents corrosive agents from reaching the metal surface and reacting with it.
Sacrificial coatings are layers of material that are more reactive than the metal substrate. This type of coating is typically made from metals such as zinc or aluminum, and when it is exposed to corrosive agents, it reacts with them instead of the metal substrate. This sacrificial reaction protects the metal substrate from corrosion.
Anti-fouling coatings are used to prevent the buildup of organisms such as algae and barnacles on marine structures, and fire-resistant coatings, which are used to protect structural steel from fire damage.
There are also several other types of protective coatings, including inhibitive coatings, which contain chemicals that work to prevent corrosion, and combination coatings, which are made up of two or more of the coating types previously mentioned.
Industry applications of protective coatings are numerous and span automotive, aerospace, marine, construction and oil and gas industries. For example, automotive manufacturers use protective coatings to prevent corrosion on car bodies and components, while the aerospace industry uses coatings to protect aircraft from corrosion and to improve their aerodynamic properties. Coatings may be applied by spraying, welding, plating or through the use of hand tools specific to the application.
There are no specific formulas related to protective coatings, as the composition and properties of the coating will vary depending on the specific application.
Materials normally used in protective coatings are myriad, spanning from polymers, epoxies, and polyurethanes (for non-metallic coatings) to zinc, aluminum and chromium (for metallic coatings).