A vapor corrosion inhibitor (VCI) is a chemical substance that gradually vaporizes at room temperature. It can be a single compound or a mixture of several compounds.

Vaporized corrosion inhibitors act electrochemically on metal surfaces to form an atmosphere that inhibits and prevents corrosion. They either chemically adsorb onto metal surfaces, or react with the metal to form a protective film.

VCI molecules float and cover the metal surface, shielding it from moisture, oxygen, and harmful substances such as acids. This prevents rust from forming, ensuring long-lasting protection.