VCI / VpCI

What means VCI

The definition of corrosion inhibitor favored by the National Association of Corrosion Engineers (NACE) is a substance which retards corrosion when added to an environment in small concentrations. Corrosion Inhibitor function by one or more of these mechanisms:

  1. By adsorption as a thin film on the surface of a corroding material
  2. By inducing formation of a thick corrosion product
  3. By forming a passive film on the metal surface
  4. By changing characteristics of the environment either by producing protective precipitates or by removing or inactivating an aggressive constituent.

Unlike the protective coating and desiccant methods, the VCI method offers both active and passive corrosion protection. The chemical corrosion process is actively influenced by vapor phase and contact phase inhibitors. The VCI molecules are deposited on the metal surfaces as a monomolecular layer and inhibit corrosion.

VpCI stands for Vapor-phase corrosion Inhibitor and is a registered Trademark to the Cortec® Corporation to make clear that Cortec® VCI's have a real Vapor-phase Corrosion Protection and not only a contact phase as most of the VCI do.

How VpCIs Work

VCI-Schaubild
Ionic Action of VpCI™ Creates a Molecular, Inhibiting Layer.
Vapor-phase corrosion inhibitors deposit from a vapor phase on the metal surface to be protected. Therefore, Vapor-phase corrosion inhibitors are protecting as long as there is sufficient inhibitor in the vapor phase surrounding the metal to maintain a condensed phase on the surface. The vapor phase acts only as a transport medium from a source to the metal site.

Unlike the protective coating and desiccant methods, the VCI method offers both active and passive corrosion protection. The chemical corrosion process is actively influenced by vapor phase and contact phase inhibitors. The VCI molecules are deposited on the metal surfaces as a monomolecular layer and inhibit corrosion.