Corrosion Inhibitors Guide
9/16/20 - Zoro Staff
Corrosion is the most common cause of equipment deterioration and can result in costly repairs.
This type of deterioration frequently occurs on car parts, outdoor tools, appliances, screws, bolts, and other metal surfaces—the result of which is usually reduced usability or lifespan.
On a larger scale, corrosion can result in the costly repair of highways, bridges, buildings, chemical processing units, and wastewater treatment plants. Corrosion inhibitors were introduced to slow down or eliminate corrosion and reduce expensive repairs. But what are corrosion inhibitors and how do they work?
Corrosion inhibitors are made of chemicals that are designed to slow down or prevent corrosion. But these chemicals can’t be so strong that they interfere with any part of the thing they’re trying to protect (typically the function of metal parts), because that would create other issues.
To understand how corrosion inhibitors work, you must first know a little bit about why corrosion happens at all. Corrosion occurs when metal is oxidized by its surroundings. The cause of this oxidation is usually oxygen combined with an electrolyte (usually water).
During corrosion, oxidation occurs at the anode (an electrode through which positively charged current flows in), causing a reduction reaction at the cathode (an electrode through which conventional current flows out). The byproduct of these interactions is hydroxyl ions, which then interact with metal to produce rust.
Corrosion inhibitors work by delaying either the oxidation or reduction process, or both. For this reason, they can be classified as cathodic (delaying oxidation), anodic (delaying reduction), or mixed (delaying both).
What Are the Ingredients for Corrosion Inhibitors?
What is in corrosion inhibitors that prevents oxidation? Popular active ingredients include chromates, nitrates, molybdates, and tungstate. These all slow the cathodic reaction. Organic inhibitors have also become increasingly popular due to the environmental impacts of non-organic inhibitors. These work slightly differently, usually displacing water molecules on the surface and forming a compact barrier.
How Do Vapor Phase Corrosion Inhibitors Work?
Vapor Phase Corrosion Inhibitors (VCI) work differently than other inhibitors by releasing compounds into the air that form bonds with a metal surface, creating a natural and passive oxide layer on the metal. Like other inhibitors, this process doesn’t interfere with other physical properties or functionalities of the metal.
What Corrosion Inhibitors Are Used in Antifreeze?
Many brands of antifreeze contain corrosion inhibitors in order to protect the metal parts involved in the cooling systems of automobiles. Most commonly these include silicates, which last within the antifreeze for about two years before requiring replacement. Even though corrosion inhibitors in the coolant fluid prevent corrosion, it’s important to also note that too much coolant corrosion inhibitor can be harmful to other parts of your cooling system.
Among common brands of corrosive inhibitors are CRC, WD-40, and Fluid Film. They can be purchased as sprays, by the gallon, or in other forms to best serve your needs. Understanding the practical use of these products can save you money in the long run and preserve the life of your equipment.
Product Compliance and Suitability
The product statements contained in this guide are intended for general informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness, accuracy, completeness, correctness or currentness of the information provided. Information provided in this guide does not replace the use by you of any manufacturer instructions, technical product manual, or other professional resource or adviser available to you. Always read, understand and follow all manufacturer instructions.
