How do Zerust products prevent corrosion?

The vapor corrosion inhibitor portion of Zerust products is made of proprietary chemical formulations that are invisible, odorless, non-toxic, non-reactive, non-flammable and non-allergenic. These chemical formulations release a corrosion inhibiting vapor that diffuses throughout an enclosure that either contains Zerust VCI formulations or is made from Zerust VCI materials, and settles on exposed metal surfaces to form a microscopic corrosion inhibiting layer.

This protective layer will remain on the surface of the metal as long as there is no significant, continuous exchange of air within the enclosure. Ideally, there should be less than one air exchange per day (for example, when an electrical cabinet or package is opened briefly and occasionally). Once the metal part is removed from the enclosure, the corrosion inhibiting layer is no longer kept in place by equilibrium with the Zerust source, and it dissipates from metal surfaces (typically within about an hour) leaving the metal part clean, dry and corrosion-free.

The vapor diffusing properties of our corrosion inhibiting formulations offer an important advantage over conventional inhibitor coatings since the traces of these gas molecules penetrate into inaccessible crevices, gaps, and slots, reaching the surfaces of complex-shaped articles that are difficult to coat. They are adsorbed onto the surface of the metal to form a corrosion inhibiting protective layer that is just a few molecules thick.

Zerust ICT products offer corrosion protection without having to be in direct contact with or coated onto the parts that are being protected. Metal parts merely need to be enclosed in or with a Zerust product (where airflow is minimized) for protection to occur. With Zerust, it is no longer necessary to apply messy oils, greases and other corrosion protection compounds and incur the cost of their removal.

What is corrosion?

Corrosion is the chemical or electrochemical reaction between a material, usually a metal, and its environment that produces a deterioration of the material and its properties. Usually corrosion is the oxidation of metals in the presence of water or water vapor, and is known as rust (iron, steel) white rust (galvanized steel), and other terms of corrosion failures such as tarnish, pitting and flaking.

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, microbiologically influenced corrosion, etc. From an economic safety and aesthetic standpoint, atmospheric corrosion is one of the most important types of corrosion. Atmospheric corrosion is enabled by atmospheric humidity and stimulated by pollutants in the atmosphere such as acid gases [sulfur dioxide (SO2), hydrogen sulfide (H2S), and carbon dioxide(CO2)], nitrogen oxides (NO and NO2), ozone (O3), and salts (chlorides and sulfides).

What is VCI?

VCI stands for Volatile Corrosion Inhibitors. Zerust applies VCI technology to inhibit corrosion on metal. All Zerust products function similarly in that they release very low concentrations (typically in parts per ten-thousandth) of invisible corrosion inhibiting vapors into the surrounding air. The vapor molecules subsequently condense onto exposed metal surfaces and form a molecular corrosion shield that can protect against rust and other forms of corrosion for up to five (5) years, and even longer in some cases.

How is corrosion prevented?

There are many different ways to prevent corrosion, including modifying the atmosphere by dehumidification, nitrogen purge, evacuation, etc, and creating a barrier on the metal surface to prevent the permeation of moisture. This barrier can be formed by 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. Flambeau Zerust impregnated products) to metal surfaces. These molecules settle on metal surfaces and form a protective corrosion inhibiting layer that inhibits the electro-chemical reactions that cause corrosion to form.

How long does Zerust corrosion protection remain effective?

Zerust provides effective corrosion protection for clean metals for up to five (5) years when used correctly and utilized within three (3) years from receipt. Zerust product should be stored in original packaging away from direct sunlight in conditions below 85 deg. F (30 deg. C) and 50% RH until it is ready for use.

How much Zerust must be used to provide complete protection?

Flambeau products featuring pre-injected Zerust components (e.g. dividers in Tuff Tainers or tabs included in weapon storage cases) are produced to contain the sufficient amount of Zerust needed for the volume of the enclosed space. For larger enclosed spaces like standard market gun safes or tool chests, we recommend using our Zerust Plaques or Capsules, which contain a higher VCI concentration.

Does an effective distance or direction have to be considered?

Almost all Zerust products are active on both sides, i.e. either side can be oriented toward a metal surface. This increases the effectiveness of the protection. No attention needs to be paid to a possible effective distance.

What happens after Zerust has been removed?

After removal of Zerust packaging, the VCI substances present on the metal surface disperse within one to two hours.

How does moisture in an enclosed space affect the performance of Zerust products?

Zerust continues to provide protection in the presence of light moisture, e.g. environments with high humidity. Corrosion problems arise when the component you are trying to protect remains in constant contact with or submerged in standing water or when moisture is allowed to enter a package unimpeded. Furthermore, Zerust will not perform to its full potential when there is a significant hole in the enclosed space around the equipment you are trying to protect because the corrosion inhibiting molecules are allowed to escape, thus breaking up the protective corrosion inhibiting molecular layer that had formed on the surface of the metal. An unimpeded airflow into the package must be avoided.

What can be anticipated when Zerust is applied to parts that are already corroded?

When parts in an already corroded condition are packaged in Zerust products, the corrosion process is slowed. However, Zerust cannot remove corrosion that has already formed.

What can be anticipated when wet parts are placed in Zerust products?

When wet parts are placed in Zerust products, a certain amount of corrosion can be anticipated to take place though Zerust will significantly slow the corrosion process. The amount of corrosion will be a function of the time it takes for the active corrosion inhibiting molecules to saturate the enclosure, the amount of moisture on the part, and the pH and contamination of the water itself.

How long can parts be expected to remain free of corrosion after removal from contact with a Zerust product?

Tests performed with electron spectroscopy for chemical analysis (ESCA) show that 2-4 hours after a steel panel is removed from a Zerust product, all traces of the corrosion inhibiting molecular layer are gone from the surface of the part.

The period of time before one can expect corrosion to occur on a part depends on the cleanliness of the part and the environment around the part (relative humidity, presence of pollutants or wood, temperature, etc.)

How long does it take for the interior of a Zerust product to reach its designed corrosion prevention capability?

The time required for active corrosion inhibiting molecules from Zerust product to saturate a package is a function of the volume and temperature of the package. Protection begins as soon as corrosion inhibiting molecules reach the metal surfaces, and maximum protection is achieved when the entire environment of the package is saturated with the corrosion inhibiting molecules.

Does Zerust have any effect on electrical or electronic components?

Test data show that Zerust products do not adversely affect electrical and electronic components. In fact, the corrosion inhibiting molecules actually help improve the reliability of electrical and electronic components by preventing corrosion that is too small to be seen by the naked eye. It is absolutely safe to use Zerust products to prevent corrosion of any instruments, devices and equipment which contain electric and electronic components.

Are there any inhalation or contact risks with Zerust products?

Test data and review of corresponding scientific literature show that there are no inhalation or contact risks with Zerust products. Zerust products have been reviewed and cleared for use by factory, government and military personnel by the appropriate occupational health departments, including those of all major automotive manufacturers worldwide.

What is the best way to store Zerust ICT products before use?

NTIC recommends keeping Zerust ICT packaging products clean, out of direct sunlight and away from water while in storage. Simply keep the products in their original shipping cartons, bags or containers. If a carton is opened, cover the products with a sheet or bag of plain polyethylene to protect the products from dust and dirt. It is also recommended that Zerust ICT products be stored in moderate temperatures, typical of most indoor workplace conditions to minimize exposure to excessive temperatures and outside elements such as direct sunlight, rain or snow. Storing Zerust ICT products correctly ensures that the products will meet or exceed their estimated shelf life.