Before understanding the anti-corrosion mechanism of VCI anti-rust film, we need to know what VCI is – VCI is an abbreviation for Volatile Corrosion Inhibitor, a corrosion inhibitor synthesized with special ingredients. China Safe VCI Film is a product that utilizes volatile corrosion inhibitors in anti-rust film. The anti-rust agent continuously volatilizes anti-rust gases, forming a certain vapor pressure, filling the sealed space, thereby achieving the ultimate goal of inhibiting metal parts from rusting. Because this method offers a long anti-rust period, is easy to operate, and has low costs, China Safe VCI Film is favored by many manufacturers.

China Safe VCI Film's Corrosion Inhibition Mechanism

Due to the complexity of metal corrosion and inhibition processes and the diversity of corrosion inhibitors, it is difficult to explain them with a single theory. The main corrosion inhibition mechanisms are as follows:

Adsorption Corrosion Inhibition Mechanism

This is a mechanism similar to chemical and physical adsorption. Because the molecular structure of the corrosion inhibitor is similar to that of a surfactant, both are composed of a polar group and a non-polar hydrophobic group. The corrosion inhibition mechanism is as follows:

The polar group of the electron donor coordinates with the metal surface, forming chemical or physical adsorption, causing the metal surface to form a double-layer structure. The non-polar group is oriented, forming a hydrophobic layer, making it difficult for H3O+ ions to approach the metal, thus inhibiting the corrosion reaction.

Film-Forming Corrosion Inhibition Mechanism

The corrosion inhibitor reacts chemically with the ions of the corrosive medium, forming an insoluble compound film on the metal surface, preventing the corrosion process and playing a role in corrosion inhibition. A large portion of these corrosion inhibitors are oxidizing agents, such as chromates, dichromates, nitrates, and nitrites. They chemically react with the metal to form a protective oxide film on the metal surface, thereby mechanically separating the metal from the medium.

Electrode Process Inhibition Mechanism

This mechanism suggests that VCI corrosion inhibitors achieve their corrosion inhibition effect because they inhibit the electrochemical process of the metal in the corrosive medium, slowing down the rate of electrochemical corrosion. Anodic inhibitors, also known as passivating agents, inhibit metal dissolution by forming a dense oxide film on the metal surface. The anions of anodic inhibitors migrate to the anode surface, causing metal passivation. Cathodic inhibitors, also called cathodic corrosion inhibitors, shift the metal corrosion potential negatively in the medium, increasing the overpotential for hydrogen evolution in acidic solutions, thus slowing down the cathodic process and reducing corrosion. Cathodic inhibitors typically involve cations migrating to the cathode surface, forming a chemical precipitate film that protects the metal from corrosion.

The above are the three mechanisms explaining the excellent anti-corrosion effect of China Safe VCI Film. We hope this information is helpful. If you would like to learn more about China Safe VCI Film, please continue to follow our website. We look forward to cooperating with you.