TechCorro Volatile Corrosion Inhibitors (VCIs) from ARMOR can reduce a metal's susceptibility to hydrogen embrittlement. TechCorro VCI molecules attach themselves to metal surfaces forming an invisible thin film. The VCI film will passivate the substrate, inhibit oxidation, and provide a barrier on the metal surface. This leads to a reduced susceptibility to hydrogen embrittlement.
What is Hydrogen embrittlement?
Hydrogen embrittlement is the process where metals become brittle following exposure to hydrogen. Hydrogen is first adsorbed onto the metal surface before penetrating the metal lattice in ionic form as protons. Hydrogen protons re-combine in lattice dislocations (micro voids) forming hydrogen molecules. The hydrogen molecules are unable to diffuse out of the metal matrix and will build pressure inside the micro voids. This hydrogen pressure will cause a marked loss in the plastic strain capacity of the metal, reducing the ductility and tensile strength.
Hydrogen embrittlement can occur during manufacturing processes, storage, or operational use - anywhere that the metal comes into contact with atomic or molecular hydrogen. Common ways in which hydrogen is introduced to the metal matrix include corrosion, chemical reactions on the metal surface and contact with acids or with other chemicals such as hydrogen sulphide or even water.
How do Volatile Corrosion Inhibitors work?
TechCorro VCIs are engineered highly specialised corrosion inhibitors based on aliphatic and nitrogen containing salts. The salts disassociate to form ions, permeating the packaging environment with corrosion inhibitors. The inhibiting ions are attracted to, and deposit on, metallic surfaces displacing moisture in the process and re-associating to form a stable nano-coating only a few molecules thick.
Components in TechCorro VCIs reduce the activity of hydrogen in the environment and on the metal substrate. Nitrogen-containing organic and inorganic compounds inhibit hydrogen from forming ionic protons. VCI molecules passivate the metal surface neutralising the effects of chemical contaminants. TechCorroâ¢ VCI nano-coating also forms an effective barrier to help prevent hydrogen-donating chemicals from coming in contact with the metal substrate.
Get in touch for free advice on corrosion packaging technology problems or for information on how to improve your corrosion protection and protective packaging technology and save costs for your business.
Kobrin, G. Metals Handbook, Vol. 13, Corrosion, 9th Edition. Metals Park, OH. ASM International, p. 321, 1986.
Did you know your Corrugated Cardboard packaging could be causing corrosion?
When using corrugated cardboard in packaging, it is important that the cardboard is
specially treated or the acidity that is oftenn present in the fibres can transfer to the metal part(s) causing corrosion. Cardboard sheets are often used to separate one row of parts from another in a package. If the cardboard is not treated, the cardboard will absorb moisture in storage and transit and will induce corrosion on the surface of the parts that is in contact with the cardboard.
In the manufacturing process of corrugated cardboard, the pulp is dissolved by nitric
acid. This acid has to be neutralised using several rinsing steps. To save money, some
manufacturers shorten these rinsing steps and consequently there is acidic residue that remains in the pulp used to make the cardboard. Additionally, some of the glues
used can add to the corrosion hazard. During transportation, especially during night hours when the temperature goes down and relative humidity goes up, porous packaging like corrugated cardboard absorbs moisture and it activates any acidic residue left behind. If the cardboard is in direct contact with the metal parts, it can easily lead to corrosion by providing an acidic electrolyte as demonstrated in the photo to the right.
As a solution, the surface of metal parts should never be allowed to touch corrugated cardboard. A sheet of VCI film or paper (such as TechCorro™[F] VCI film or TechCorro™[P] VCI paper) should be placed between the cardboard surface and
the metal part (as shown in the photo below). A sheet of VCI film should also be placed on the top row of parts to prevent the cardboard from touching the row of parts immediately below it. Another approach would be to insert the cardboard sheet into a flat bag made of VCI film thereby covering both sides of the cardboard sheet.
Assessing the shipping and packaging conditions and other variables that can influence corrosion formation allows for the design and use of protective packaging solutions that will preserve and protect. While moisture cannot be completely removed from the packaging, porous packaging materials reduce relative humidity and condensation (as long as they are not acidic porous packaging which can actually increase corrosion as described above). TechCorro™ VCI Nanotechnology, found in Technology Packaging’s product line, responds and adjusts to temperature and humidity fluctuations, increasing and decreasing as needed.
Free Advice On Corrosion Preventative Packaging Solutions
For more information on how corrosion preventative packaging can help your business please call us on 020 3598 1919 or email email@example.com