Corrosion is one of the biggest threats facing metal products. While most metals have high corrosion-resistance, external variables such as moisture, gases, and chemicals can affect metal’s physical and chemical composition. There is no wonder that when metals undergo the corrosion process, their functionality and quality become compromised.
What Causes Corrosion?
Corrosion is a naturally occurring event in metals that require three conditions: a metallic surface, moisture, and an oxidizing agent. When metal surface comes in contact with the oxidizing agent, the chemical reaction that takes place causes metal to deteriorate in composition and appearance. Rust is the most common form of corrosion.
The electrochemical properties of a certain type of metal determine the types of corrosion metals are vulnerable to. For example, rust forms in iron tools when exposed to moisture over long periods while copper tarnishes under changing weather conditions.
Can Corrosion be Prevented?
Some of the methods metal fabricators and manufacturers use to prevent metal corrosion include the following:
Corrosion control begins with proper planning and design. The design should allow air to circulate and minimize moisture penetration. Metal joints should be welded and crevices and cavities should be avoided to prevent fluids from entering and remaining stagnant. In environments frequently exposed to water, drain holes should be considered to allow water to drain off instead of collecting inside.
Coatings such as powder coating provide an extra layer of protection on a metal’s surface. Before powder coating is applied, the metal product undergoes the process of sandblasting or the application of abrasive materials to remove impurities like paint, rust, and dirt from the metal’s surface. Sandblasting gives the surface a clean, white finish and prepares the metal for the powder coating process. Powder coating may come in different compositions including acrylic, epoxy, and urethane.
Galvanizing is a type of cathodic protection where a protective zinc coating is applied to steel to prevent corrosion. The zinc coating becomes the sacrificial anode which corrodes in place of the encapsulated steel.
Corrosion inhibitors are chemicals that when added to a metal’s surface, produce a protective film that reduces the rate of corrosion. The formation of the protective film is affected by temperature, chemical composition, and the pH level of the environment. Aluminum oxide, copper carbonate, and titanium oxide are some examples of inhibitors which are applied via the process of passivation.
Corrosion occurs when there is a chemical reaction between the metal and its surrounding environment. Environmental controls may be done to minimize or slow down corrosion, for example, reducing the exposure to seawater or rain or regulating the quantities of oxygen, sulfur, and chlorine in the environment.
Coatings, environmental modifications, and corrosion inhibitors help protect metals from corrosion but regular maintenance is equally important in preventing corrosion. Always look out for early signs of rust and remove them immediately. Make sure to keep parts clean and dry and apply additional protection if necessary.
Preventing or slowing down corrosion is possible, however, there is no one-size-fits-all solution in doing so. All stages, from design to manufacturing and maintenance need to be considered to control corrosion in different metals.