Corrosion inhibitors are substances that, when added in small amounts to a corrosive environment, slow down the rate of corrosion. In fact, an inhibitor can be considered a retarding catalyst. There are many inhibitors available with different compositions.

Corrosion inhibitors are additives that control corrosion by altering the metal surface, the environment, or both. Their mode of action is to alter the anodic, cathodic, or both reactions. There are many corrosion inhibitors available with different compositions. Most of these materials have been discovered and refined through experimental testing, and many of them are sold under trade names and their chemical composition is kept secret.