VCIs vs Desiccants. How do they Differ?

Often people confuse VCI (Vapor or Volatile Corrosion Inhibitor) with desiccants, as they both are used to control corrosion during shipping and storage.  However, the way these chemistries work is much different. Depending on the application, environment and length of protection, you may get better results with VCI versus desiccants. Some highly effective packaging systems use both chemistries. So, lets clear up some confusion around these two useful products.


Desiccants function is to draw and retain moisture from the environment and prevent it from reacting with the metal surface.  While various desiccant products have different absorption rates, capacities, effective operating temperatures and other considerations, they all work by absorbing the moisture in the airspace. As new moisture passes into the area to be protected, the desiccant will eventually become saturated and no longer reduce the corrosion rate.  After the desiccant has reached its capacity to absorb liquid it is important that the desiccant is removed and replaced. A fully saturated desiccant will begin to release moisture back into the air space and can increase the corrosion rate of the metal it’s intended to protect.


  • Desiccant products are inexpensive.
  • Desiccant products are clean, dry and environmentally safe.
  • Desiccant products are easy to use and save labor costs.
  • Desiccant products present virtually no health concerns.


VCI- Volatile/Vapor Corrosion Inhibitors

VCIs are substances that slowly release a corrosion preventative compound that are capable of protecting metal surfaces. VCIs are often used in situations where it is impractical or undesired to use rust preventative liquids or other surface treatments.

The compounds that VCIs release into an airspace actively prevent corrosion by forming strong bonds with a metal surface. This promotes and maintains the natural and healthy passive oxide layer on the metal surface. 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 package without further cleaning.

VCIs are formulated to most commonly protect ferrous metals such as iron, cast iron, carbon steel, chrome, etc. Many specialty VCI products are also available to protect non-ferrous metals such as copper, brass, and bronze from corrosion and tarnish. VCIs are delivered in formats of poly packaging, kraft paper, emitters, and powders.


  • VCI products provide robust corrosion protection
  • VCI products are clean and dry, parts are ready to use right out of the packaging.
  • VCI products are easy to use and save labor costs.
  • VCI products last many years
  • VCI products can be custom-printed with your company logo or other information.
  • VCI products are less costly than most other corrosion products.
  • VCI products are safer than oils and greases.

The good news is both products can be used in packaging programs to leverage the benefits of each type. For example, a package could be lined with a VCI gusset bag and a desiccant can be added to stabilize them in shipping.  Whichever option you choose, FlexPAC can help you with your corrosion prevention needs. We analyze the current state of your corrosion management needs and work with you and your team to implement the best and most cost-effective solution. FlexPAC in partnership with Zerust Technical Support team members, can come to your facility and do a step-by-step analysis of your current process including fluid audits, VCI and packaging process audits, and data logger analysis. Our mission is to provide you with the right products, processes, and procedures to ensure that you can achieve your desired results.

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Our corrosion prevention program can help keep your metals safe year-round.