Volatile corrosion inhibitors (VCI) are a type of corrosion inhibitor that are used to protect ferrous materials and non ferrous metals against corrosion or oxidation where it is impractical to apply surface treatments. They slowly release compounds within a sealed airspace that actively prevents surface corrosion. A typical application is to protect stored tools or parts inside bags, boxes or cupboards, one advantage of VCIs being that if the container is opened and reclosed, levels of inhibitor will recover.
Contents
History
The history of VCI's also known as VpCI's began in the 1940s when Shell Petroleum developed the very first of the traditional VCI's using a chemical compound called DICHAN or Dicyclohexylammonium Nitrite. This was used by the US military to prevent various metal components from corrosion and used it in multiple formats such as VCI paper, VCI powder, VCI solutions etc. Due to the dangerous nature of the chemistry DICHAN is now a mostly banned substance and there was a distinct break in the development of VCI's into two major groups of nitrite based VCI's and Amine based VCI's. The inclusion of either nitrite, secondary and tertiary amines is now frowned upon in the packaging world as combinations of these types of chemicals can cause Nitrosamines which are cancer forming agents.
Product uses
VCI chemicals are often added to paper and plastic substrates as a medium to deliver the protective chemical compounds for use in automotive packaging, steel packaging, metal packaging, military and hobby markets.