Corrosion Inhibitors

Galvanized steel production has become a leading industry since its discovery. It protects the product by swathing other elements on its surface. Specific chemical compounds, usually single metals or alloys, are used in the process as corrosion inhibitors. Galvanization using these materials has led to the extension of the life of steel by adding to its resistance against rusting and other forms of corrosion.

Corrosion inhibitors are compounds responsible for keeping metal surfaces, especially steel, free of oxidation. The best way to prevent corrosion is to stop oxidation from occurring on the metal surface. Doing so ensures that rust will not build up. These compounds are categorized into four types: anodic inhibitors, cathodic inhibitors, oxygen scavengers and microbicides.

Anodic inhibitors are associated mostly with the passivation phenomenon. Passivation is the process of restraining oxidation by paralyzing the ability of the surface of a metal product from reacting with the elements in the atmosphere, particularly oxygen. This occurs naturally in some metallic elements. It is the same concept used in the galvanization process to improve the performance of steel by shielding it against chemical decay.

Many compounds that are considered anodic inhibitors are used extensively today in the manufacture of galvanized steel strapping for heavy cargo. Previously, the most common corrosion-inhibiting compounds were chromate, pertechnetate and nitrite. However, the use of chromate was later discouraged because of its carcinogenic properties while pertechnetate was later found to be more radioactive than uranium. Nitrite, on the other hand, though safe with low toxicity is not that effective in galvanization.

Cathodic inhibitors have a similar task with anodic inhibitors in preventing oxidation. It does this by reducing oxygen content in water or any other oxygen-containing fluid. These compounds are usually applied to products often exposed to moisture, such as galvanized steel strapping seals. Its unique chemical properties decrease the chance of corrosion developing on the metal surface.