Cathodic Inhibitors

Cathodic inhibitors specifically target the cathodic region of the metal or electrochemical cell and provide protection by inhibiting the rate of the cathodic reaction. This is generally accomplished by building a barrier layer to obstruct the corrosive agents from accessing the metal surface or by preventing the reagents in the cathodic process from forming their normal products (e.g. hydrogen gas). For example, certain inhibitors can precipitate on selected cathodic areas of the metal to form a barrier, effectively isolating the metal from the environment. Also, other inhibitors can preemptively occupy or react with hydrogen or oxygen, for example, and keep them from forming hydrogen gas or, in the case of oxygen, keep it from oxidizing the metal. Calcium bicarbonate, zinc compounds, and polyphosphates are some examples of cathodic inhibitors.