Table of Contents

Welcome to Construction Systems Supply's Anti Corrosion Coating library. This website is dedicated to providing you with an understanding of how anti corrosion coatings work, and the benefits of utilizing industrial coatings to prevent rust.

For your convenience, information on anti corrosion coatings has been broken down into five sections. Click on a link in the table of contents to be taken directly to a particular section.

rusty metal plate
cor·ro·sion:

Corrosion is the process by which metals deteriorate to their natural states through a chemical process known as reduction-oxidation. Metal undergoing this degredation is being broken down by its environment.

 
close up of rust

What is an anti corrosion coating?

An anti corrosion coating is a paint or epoxy coating that works to prevent metal corrosion and rust.

Corrosion, in simplest terms, is the process of a metal returning back to its natural state. The corrosive process is the result of metal being oxidized by the environment. The formation of rust is the most commonly recognized indication that metal is corroding.

An anti corrosion coating acts as a barrier between the metal and harsh elements, preventing metal corrosion. Metal components protected with an anti corrosion coating are less susceptible to rust and deterioration when exposed to moisture, salts and chemicals than unprotected metal.

In addition to offering protection from corrosive environments, some anti corrosion coatings also offer dual abrasion resistance and slip resistant properties.

 

Why are anti corrosion industrial coatings important?

Protective industrial coatings are a must for metal used in commercial and industrial applications, such as: steel bridges, pipelines, construction equipment, chemical plants and machinery on manufacturing floors. The two most common forms of industrial coatings are polyurethane and epoxy coatings.

Utilizing industrial coatings to manage and prevent the corrosion of steel structures is of the utmost importance for both human and environmental safety. Corroding steel in concrete can weaken buildings and dams. Corroding bridges develop weak spots and risk collapse. Corroding pipes can crack and leak, contaminating water supplies.

In 2006, corrosion caused a dime-sized leak in a pipe running oil to the Trans-Alaska Pipeline that resulted in about 267-thousand gallons of oil spilling out over the Alaskan tundra (source: New York Times).

Corrosion not only has adverse effects on safety and the environment, it also has a negative impact on the economy. According to a 2002 study by the National Association of Corrosion Engineers (NACE International), corrosion prevention in the U.S. cost an average of $276 billion in 1998 (source: NACE). In the U.S. and other countries where studies on the costs of corrosion have been carried out, corrosion costs have ranged between 2% to 5% of the gross national product(source: Corrosion Journal).

Corrosion can take many forms, some of which include:

  • Pitting
  • Blistering
  • Erosion
  • Galvanic Corrosion
  • Crevice Corrosion
  • Stress Cracking

Industrial coatings can help to protect metal from corrosive elements like alkalis, sewage, chemicals, and salts.

tanks before and after coating boiler before coating boiler after coating
 

Why does metal rust and corrode?

When metal is not properly protected with an anti corrosion coating, it eventually begins to return to its natural state (ore) through a chemical process known as metal corrosion. Corrosion usually begins at a point where the metal is under stress

The corrosion process begins the moment the finished meal is exposed to oxygen (from the atmosphere) and water (which acts as an electrolyte in the electrochemical reaction of corrosion).

Electrochemical metal corrosion is caused when an oxidant (such as oxygen) and an electrolyte (such as water) come in contact with a metal surface (such as iron) and create an electrical circuit in which electrons flow through the metal. The flow of electrons from a high energy area (anode) to a low energy area (cathode) causes the metal to oxidize and from rust.

One of the most common forms of metal corrosion is galvanic corrosion. Galvanic corrosion occurs at the point that two electrochemically dissimilar metals touch. When two electrochemically dissimilar metals come in contact with each other and are exposed to an electrolyte, one metal serves as the (anode) and the other as the (cathode). This results in one metal corroding faster than it would on its own, and the other metal corroding slower than it would on its own.

Another common form of corrosion is biological corrosion, which is caused by certain types of fungi, algae, and bacteria. These living organisms can break down metal as part of their metabolic process.

Properly applied anti corrosion coatings can help to protect metal from electrochemical, galvanic and biological corrosion.

biological corrosion corrosion diagram
 

How does an anti rust coating prevent corrosion?

Anti rust coatings are corrosion resistant coatings that provide a barrier between corrosive environments and metal. In addition to preventing metal corrosion, anti rust coatings can enhance aesthetics and improve abrasion resistance.

When a corrosion resistant coating is applied to metal, the metal is essentially becoming electrically insulated. Anti rust coatings are chemically impermeable and suppress the electrochemical reaction required for the formation of rust and oxidation.

For a corrosion resistant coating to work, it must be applied uniformly to the whole piece of metal. The slightest pinhole in a corrosion resistant coating can cause the coating to fail over time and allow for the corrosion process to begin.

failed coating
 
roll on coating

What kind of anti corrosion coating do I need?

There are several types of anti corrosion coatings on the market, depending on your particular needs. Anti corrosion coatings come in a variety of forms, the two most popular being epoxy and polyurethane. These polymer anti corrosion coatings are typically sold either as a liquid (for spraying on) or a paste (for rolling on).

A polymer anti corrosion coating tends to be the most economical option, offering excelling adhesion properties in damp environments and the ability to be reinforced with impact resistant KevlarR. Some paste forms of polymer coatings may even be applied underwater.

For metal that will be routinely exposed to chemicals, salts and sewage, hybrid Novolac anti corrosion coatings offer superior chemical resistance and long-term wear resistance. These industrial coatings can be ceramic-filled for added strength.

For metal water tanks and pipes, it’s important to select an anti corrosive coating that has been specially certified for drinking water.

Learn even more about anti corrosive coatings.