Vapour corrosion inhibitors (VCIs) prevent corrosion caused due to humid atmospheric conditions. However, before getting into how VCI works, it is necessary to understand how corrosion takes place. When a metal gets in contact with moisture, the process results in the formation of electrolytes. This completes an electrical circuit, and as a result, electrons from the high-energy areas start flowing to the low-energy areas.
All the ingredients of vapour corrosion inhibitors or vapour phase inhibitors volatilise to release their molecules into the air. This helps to prevent corrosion on the metal surface by blocking the effect of the electrolytes. Scanning with electron scanning equipment has shown that when an atmosphere is rich in vapour corrosion inhibitors, the VPI molecules condense and form a microscopic layer on the surface.
What are the features of high-quality VCIs?
Vapour corrosion inhibitors are available in multiple forms. Among these, the VCI tablets and pellets are the most popular. These products are also known as COROTABS. Let’s look at some features that are noticeable in VCI solutions from the leading brands:
- These products come with proprietary chemical systems that can volatise at room temperature to create a protective layout. If the atmosphere contains moisture, the layer would permeate it and stop it from causing corrosion.
- Upon volatilisation, COROTABS forms a corrosion preventive film on the interior portion of the enclosed spaces they are applied to. This makes these products highly effective in protecting the interior of pipes, tanks, condenser coils, and other voids with metallic walls.
How does VCI work?
After application, the vapour corrosion inhibitors start to vaporise. The vapourised VCI molecules then automatically align themselves over the surface of the metal, forming a barrier. The protective layer starts to spread all over the surface, covering even the hard-to-reach parts.
As the metal surface is charged in nature, the polar orientation of the VCI molecules causes them to stay attracted to the surface. The barrier caused by the layer prevents oxygen and other corrosive substances from reaching the metal surface. Thus, oxidation does not take place, and thereby preventing corrosion.
What makes VCI a great rust-preventive solution?
Several factors have caused vapour corrosion inhibitor manufacturers in India to become a popular choice among rust preventive techniques. Unlike many of the other solutions, these aren’t oily or greasy. In applications where it would be undesirable to add a layer of rust-preventive oil to a metal surface, VCI is the perfect alternative. Moreover, as vapour rust inhibitors volatilise and get deposited, it is possible to protect even the parts of an item where it would be difficult to apply the other solutions.