What is VCI?

When it comes to VCI anti-corrosion ingredients, VCI can stand for either of these two phrases. Both mean, and refer to, the same thing:

1) Vapor Corrosion Inhibitor
2) Volatile Corrosion Inhibitor

How does VCI work?

Vappro VCI works by emitting VCI molecules into the surrounding area, within an enclosure, until it is completely saturated. These Vappro VCI molecules are safe, invisible and odourless.

When the VCI molecules come into contact with the air in the enclosure, an ionic reaction takes place between the VCI molecules and the water molecules in the air.

The VCI molecules in the surrounding enclosure are hydrolized into VCI ions, which form a molecular corrosion protective barrier on the metal surface. This occurs through polarization, and thus passivate the substrate from atmospheric corrosion.

It normally takes approximately 24 hours for the VCI ions to be absorbed on the metal surface. Source: www.vappro.com 

Diagram Source: http://www.vapprovci.com/vapproworks.html

In other words, VCI works when a metal part is in an enclosed or sealed space where a VCI ingredient is present.

This could be a VCI polyethelyne (PE) bag (i.e. a plastic bag with VCI impregnated into the bag material), or it could be a normal plastic bag with a VCI emitter placed in the bag.  It could also be a crate lined and sealed with VCI plastic, or lined and sealed with regular plastic and containing VCI emitters, or it could be a crate or box of some kind that is lined with VCI paper.

This VCI anti-corrosion effect can also take place when a metal part is encapsulated in a VCI coating of some kind.

So, in layman's terms, what is happening is the VCI molecules in the bag, paper, emitter or coating are slowly leaving the bag, VCI coated paper, emitter or coating and going into the enclosed space and are reacting with the water molecules that are almost always present in an enclosed space or on the surface of an object.

After the VCI molecules are released into the enclosed area they react chemically with the water molecules (or with the water contained within any molecules present in the space). These VCI molecules and water molecules react with each other and combine to create a new kind of molecule which is now an ion molecule, a.ka. a VCI ion (or "ionized" molecule).

What is an Ion?

To understand this process better, Wikipedia explains what an ion is:

An ion (/ˈaɪən, -ɒn/) is an atom or a molecule in which the total number of electrons is not equal to the total number of protons, giving the atom or molecule a net positive or negative electrical charge. Ions can be created, by either chemical or physical means, via ionization.
Source: https://en.wikipedia.org/wiki/Ion

So, this new molecule is, essentially, magnetic due to the positive and negatively charged VCI ions, that are then attracted to the naturally occuring positive and negative ions on the metal surface. These ions gather together on the metal surface of the object(s) and neutralize the natural corrosion process taking place on the metal surface (passivate).  Essentially when these VCI ions gather on the metal surface they are creating a micro-thin barrier on the metal, protecting it from the natural process that occurs when un-treated metal or steel is exposed to water or water vapor.

What does Passivate mean?

The Google Definition explains that "passivate" is to:

"make (a metal or other substance) unreactive by altering the surface layer or coating the surface with a thin inert layer."

Source is "Google": https://www.google.ca/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=passivates

Why does metal rust in the first place?

In "very layman's terms", rust occurs because when iron, or a type of metal, is refined a lot of energy is required. Once the finished metal raw material, or finished product, is created its natural tendency is to return to its original form when exposed to air, water or the natural environment in general.

Wikipedia describes the process:

"Rust is another name for iron oxide, which occurs when iron or an alloy that contains iron, like steel, is exposed to oxygen and moisture for a long period of time. Over time, the oxygen combines with the metal at an atomic level, forming a new compound called an oxide and weakening the bonds of the metal itself. Although some people refer to rust generally as "oxidation", that term is much more general; although rust forms when iron undergoes oxidation, not all oxidation forms rust. Only iron or alloys that contain iron can rust, but other metals can corrode in similar ways.

The main catalyst for the rusting process is water. Iron or steel structures might appear to be solid, but water molecules can penetrate the microscopic pits and cracks in any exposed metal. The hydrogen atoms present in water molecules can combine with other elements to form acids, which will eventually cause more metal to be exposed. If chloride ions [salt] are present, as is the case with saltwater, the corrosion is likely to occur more quickly. Meanwhile, the oxygen atoms combine with metallic atoms to form the destructive oxide compound. As the atoms combine, they weaken the metal, making the structure brittle and crumbly." Source: https://en.wikipedia.org/wiki/Rust

So, what is happening, essentially, is the iron and steel is combining with, and reacting with, the natural environment and causing the man-made product to return to its natural, pre-refined form.  It's "rusting".

You'll notice "rust" looks a lot like iron ore:

Rust:

Photo Source: https://en.wikipedia.org/wiki/Rust

Iron Ore:



Photo Source: https://hypocentre.wordpress.com/2012/04/page/3/
This is iron ore from Belo Horizonte, Brazil

If you have any questions, please feel free to contact me via the contact form on the right side of this page.