ABSTRACT

The oil and gas industry has a tremendous need for the protection of assets during shipment and storage. Newer advances have allowed the use of the vapor corrosion inhibitor technology to be incorporated into temporary coatings which are designed to provide corrosion protection in extreme environments, yet still be easily removable compared to the older traditional wax type coatings made from hydrocarbons. By incorporating the vapor corrosion inhibitor technology into these temporary coatings, it allows the use of thinner film thicknesses and less reliance on a thick barrier to keep contaminants away from the surface. 1, 2

Technology Background

Types of VCIs

VCIs are a corrosion inhibitor technology which is comprised of very small particles which are attracted to a metal substrate. They come in various formulations which are dependent on the type of system they will be used in, for example films, oils, coatings, cleaners, etc. There are also a variety of formulations which provide protection in ferrous, non-ferrous or multi-metal applications. Other variables include the amount of vapor phase compared to contact phase inhibitors.

How Vapor Corrosion Inhibitors (VCIs) work in a coating

VCIs are formulated into a coating thru a complex development process which involves determining chemical compatibility of the VCIs with the other components of the coating such as the resin, solvents, pigments and other additives used for a variety of reasons.

VCIs work by adsorbing onto the metal surface in a non-reactive attractive capacity, in other words, they are attracted to the metal through the particle charge3

How VCIs compare to traditional inhibitors

Traditional inhibitor systems use inorganic metal particles such as zincs, chromates, aluminum and others. Additionally, traditional inhibitor systems often rely on thick barriers to prevent moisture and oxygen from getting to the substrate. VCIs compare with traditional inhibitor systems by using smaller particles as well as relying not only on contact inhibition but also vapor phase inhibition, providing more complete coverage and protection of the surface. This can be illustrated as follows:

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