The effectiveness of corrosion inhibitors are largely determined by the electrochemical potential of the metal that is to be protected. Corrosion inhibitors are used to prevent or delay corrosion initiation. It can either influence the anodic or the cathodic reactions, or both. It is normally divided into five groups, such as anodic, cathodic, organic, vapour phase and oxidizing corrosion inhibitors. Anodic corrosion inhibitors, which inhibit corrosion, associated with the stabilization of the passivity film, tend to break down when chloride ions are present at the steel surface.