Molekulaarsuurust

Molekulaarsuurust, often translated as molecular acid rust, is a form of corrosion that occurs when metal surfaces are exposed to acidic environments at a microscopic level. Unlike conventional rust, which results from the oxidation of iron in the presence of water, molecular acid rust involves the penetration of acid molecules into the metal lattice, accelerating the breakdown of the protective oxide film.

The process typically begins when acidic vapors or liquids—commonly sulfuric, nitric, or hydrochloric acids—contact metal in humid or wet conditions. Acid molecules diffuse through existing oxide layers and react with the underlying metal, forming iron salts that are more soluble than the original rust. This continual dissolution and re-oxidation lead to a thinning of the metal substrate, enhancing the rate of corrosion.

Industrial sectors most vulnerable to molekulaarsuurust include petrochemical refineries, battery manufacturing, and any facility that handles strong acids or acidic wastewater. The issue can also affect storage tanks, piping, and structural components, leading to premature failure and increased maintenance costs.

Detection methods involve electrochemical impedance spectroscopy and surface analytical techniques such as X‑ray photoelectron spectroscopy, which can reveal the presence of acid‑induced changes in the oxide layer. Preventive measures include applying barrier coatings, using corrosion‑resistant alloys, and controlling the environment’s pH and humidity.

While molekulaarsuurust is a relatively specialized term within corrosion science, its understanding is essential for designing durable metallurgical systems in acid‑heavy environments.