Corrosion of metallic surfaces can be controlled or reduced by the addition of chemical compounds to the corrodent. This form of corrosion control is called inhibition and the compounds added are known as corrosion inhibitors. These inhibitors will reduce the rate of either anodic oxidation, cathodic reduction, or both. The inhibitors themselves form a protective film on the surface of the metal. It has been postulated that the inhibitors are adsorbed onto the metal surface either by physical (electrostatic) adsorption or chemisorption.