What is corrosion?
Corrosion is the chemical or electrochemical reaction between a metal and its environment that results in deterioration of the material and its properties. Corrosion is generally initiated when atmospheric moisture (humidity) settles on metals. This moisture acts as a conductor, enabling the flow of electrons between high-energy areas (cathodes) and low-energy areas (anodes) on metal surfaces. This electrochemical process results in the visible oxidation referred to as rust (iron, steel), white rust (galvanized steel), and some other terms for corrosion such as tarnish, pitting, flaking and spalling.
There are many different types of corrosion, including atmospheric corrosion, corrosion in waters, corrosion in soils, corrosion in chemical environments, mechanically assisted corrosion, high-temperature corrosion, and microbiologically influenced corrosion. From an economic, safety and aesthetic standpoint, atmospheric corrosion is the most notable type of corrosion. Atmospheric corrosion is enabled by atmospheric humidity and stimulated by pollutants such as acid gases [sulfur dioxide (SO2 ), hydrogen sulfide (H2 S) and carbon dioxide (CO2 )], nitrogen oxides (NO and NO2 ), ozone (O3 ) and salts (chlorides and sulfides).
How corrosion is prevented?
Corrosion can be prevented by modifying the atmosphere through dehumidification, nitrogen purge, and evacuation. Another method is by creating a protective barrier on the metal surface against moisture. This barrier can be formed by a liquid coating, such as oil, or via Zerust products that contain VCI or Vapor Corrosion Inhibitors. Vapor Corrosion Inhibitors work by diffusing corrosion inhibiting molecules from a source (e.g. SteelBee Zerust impregnated products) to metal surfaces. These molecules settle on metal surfaces and form a protective corrosion inhibiting layer that inhibits the electrochemical reactions that cause corrosion to form.
What are Vapor Corrosion Inhibitors?
Vapor corrosion inhibitors (VCIs) are substances that slowly release a corrosion preventative compound into a sealed air space, effectively protecting exposed metal surfaces. VCIs are often used in situations where it is impractical or undesired to use rust preventative liquids or other surface treatments.
How do Vapor Corrosion Inhibitors work?
The compounds that VCIs release into an airspace actively prevent corrosion by forming strong bonds with a metal surface, promoting and maintaining the natural and healthy passive oxide layer on the metal. The VCI layer that forms is invisible, dry, and does not affect the physical properties or functionality of the metal in any way. The protected metal can be painted, treated and/or used straight out of the Zerust® package without further cleaning.