When it comes to controlling corrosion, two frequently used methods are VCI (which stands for Vapor Corrosion Inhibitors) and desiccant. But make no mistake, VCI and desiccant are not the same – they work in very different ways. If you want to be an Eradicator-of-Rust Superstar, then understanding their differences and the unique advantages each has to offer is your first step towards “stardom.”
When it comes to rust and corrosion of metal/metal parts, moisture, humidity and condensation are public enemy number one. In their own unique ways, VCI and desiccant protect metal parts from the damaging effects of rust and corrosion. They are similar in that they are most effective when used in an enclosed space (such as product packaging, bins, crates, containers or totes) and both VCI and desiccant are ideal for use in the storage or shipping of metal parts.
But that is where their similarities end. VCI and desiccant protect metal/metal parts in very different ways using very different chemistry. One way to explain their differences is using a give-and-take analogy — VCI “gives” or emits a vapor that ultimately forms a protective layer on the surface of metal while desiccant “takes” or adsorbs moisture from the packaging environment to keep metal corrosion free. Depending on the application and the particulars of the storage or shipping environment, one method may provide better results than the other or, as is the case in many give-and-take relationships, VCI and desiccant can often work together to provide premium protection of metal/metal parts.
The How and Why of VCI
Vapor Corrosion Inhibitors, also known as VCI, are a class of chemical compounds that emit rust-inhibiting vapors into an enclosed air space. Once the VCI vapors are released, the VCI molecules form a microscopic layer of protection on the surface of ferrous and non-ferrous metal that displaces moisture. Put more simply, the VCI forms an invisible shield on the surface of the metal that repels rust (this is no superhero mumbo jumbo, it’s just how VCI works)!
How does the VCI get into the box, bin, container or crate to release its superhero metal-protecting powers? The answer is packaging materials. VCI is embedded into packaging materials such as paper or poly film which are then manufactured into rolls, sheets, bags or tubing. When metal/metal parts are wrapped or covered in VCI packaging and enclosed for shipping or storage, the VCI is released and it kicks into gear.
VCI chemistry does not alter, effect or leave a residue on metal/metal parts. It works both on clean metal parts and those with a coating or finish. Once metal is removed from packaging, the VCI quickly dissipates and metal parts are ready-for-use. There is no need for cleaning, wiping or degreasing.
ARMOR “turned up the volume” on traditional VCI technology to create its proprietary VCI Nanotechnology™. ARMOR engineers highly-specialized corrosion inhibitors for its VCI “secret recipe” and the result is a stable, protective nanocoating on the surface of metal that is only a few molecules thick.
ARMOR VCI Nanotechnology self-adjusts to the packaging environment, adapting to the temperature or humidity. It also self-replenishes so, if packaging or container is opened for a short time and re-sealed, the VCI replenishes to re-establish the protective shield on the surface of metal. And, when it comes to protecting metal parts with unique or intricate shapes and designs, VCI Nanotechnology is able to “go where no man has gone before!” VCI vapors are able to diffuse (and protect) recessed or hard-to-reach areas of metal parts that other rust prevention methods can’t.
Desiccant – Your Ally to Keep It Dry
Desiccants are drying agents that are used to prevent moisture and humidity levels in an enclosed space. They help to control and remove moisture and condensation from sealed product packaging, bins, crates, containers or totes, to prevent corrosion and damage to metal/metal parts.
Drying agents such as silica, activated charcoal, bentonite clay, or calcium chloride are adsorbent materials used to make desiccant. To the naked eye, these drying agents appear to be a solid – typically in the form of small beads, granules or pellets. But, when magnified, you can see that their surface is porous, which explains why they are able to hold a large percentage of their weight in moisture.
Desiccant uses drying agents to perform adsorption (take note of the d in adsorption) – a process where a substance adheres to, but does not penetrate, the surface of an adsorbent material. This is not the same as absorption (take note of the b in absorption), which is the process of a substance being drawn up or taken into an absorbent material.
Why all the fuss over the clarification between adsorption vs. absorption? Because they are two different processes that are often confused. The most important take away is understanding that all desiccants adsorb moisture – that means moisture adheres to the desiccant and the desiccant retains or holds onto it in a way that it can’t escape (unless exposed to extreme temperature variations). For optimal results, it is important to use the proper size and quantity of desiccant based on the size of the metal/metal parts to be stored or shipped as well as the size and volume of the container, the physical properties of the container and the estimated length of protection.
There is no disputing that desiccant is an effective rust prevention option, but it is important to be aware of its limitations. A desiccant does one thing — adsorb moisture. Period. They do not actively protect the surface of metal/metal parts or prevent the formation of corrosion in the way that VCI does. In fact, if a desiccant packet becomes saturated and it is in contact with metal, it can actually cause rust to form in the areas where the two are touching. For most desiccant applications, it is recommended that desiccant packet(s) be inserted in the product packaging in an area where it will not touch metal/metal parts.
Acting as a dehumidifier to your packaging is what desiccant does best but, what happens when you combine these moisture-minimizing powerhouses with VCI packaging? Rust and corrosion don’t stand a chance. Desiccants used in combination with VCI are the perfect pair for highly-demanding packaging environments. While VCI packaging serves as the “first line of defense” offering both a physical barrier and a blanket of protection on the surface of metal to shield against environmental conditions, desiccants “bring up the rear” as they minimize moisture and condensation.
In 2019, ARMOR formally combined VCI and desiccant together to create its SMARTY PAK™. These new power PAKs are the perfect union of metal protection and moisture control packaged into one rust-prevention pouch. The SMARTY PAK design not only emits ARMOR VCI Nanotechnology, it uses a specialty desiccant that adsorbs moisture faster than traditional desiccant and holds on to the moisture even at high temperatures. Smarter yet, SMARTY PAKs are available in three sizes, they deliver multi-metal protection, and they are non-dusting and lint-free making them ideal for use in applications where fibrous packaging materials are not allowed.
If you want to learn more about how VCI and/or desiccant can protect metal parts from the harmful effects of moisture and humidity during packaging, storage, transport or export, visit the ARMOR website or contact your ARMOR sales representative.