Technical Bulletin # 1 VCI Performance in Warm-Humid Environments BENZ Packaging Solutions (P) Ltd. - Gurgaon It is a fact of nature-metals Rust and Corrode. This Process of Corrosion is happening around us all the time. It happens even more quickly when the weather is warmer. For every 10 degree C rise in temperature, Corrosion rates can double. This means that the warmer your metal part (or the air surrounding it) is, the quicker it is going to rust. In addition, relative humidity greater than 60% is sufficient to create an electrolyte on the surface of metal. The electrolyte, along with oxygen, is all that is necessary for Corrosion to form on metal surfaces. Corrosion is the natural reaction of metals with oxygen. This reaction is immediate and ongoing unless the corrosion cell is halted, or passivated. It is important to remember that the more manipulation metal endures during its processing, the more quickly it is likely to corrode. This manipulation includes cold working, stamping, forming, deep drawing, coiling, coining, and heat treatment. A Corrosion Inhibitor is any chemical or mechanism that can stop Corrosion. There are hundreds of chemicals that can be used as Corrosion Inhibitors. In addition, any type of material that can create a Barrier between the metal surface and the atmosphere will likely Inhibit Corrosion. This is how oils and greases came into use as Corrosion Inhibitors. The goal is to prevent Moisture and Oxygen from reaching the surface of the metal. VCI (Vapor Corrosion Inhibitor) Technology is an effective method of Corrosion Prevention for all types of fabricated metal parts. VCI works on a molecular, Nanotechnology level to inhibit corrosion on metal. VCI’s are a unique class of Corrosion-Inhibiting chemical compounds that contain sufficient Vapor Pressure to release molecules from the substrate into the air. Proper VCI formulations contain Inhibitors that easily Vaporize from a solid form into a gaseous form. This outgassing is an important factor in the way that VCI’s prevent corrosion. VCI works in several important ways. First, the VCI Vapors or gasses fill the enclosed space with corrosion-inhibiting compounds. Once this space is full of the VCI, or VCI-rich, the Vaporization ceases. The Vapors effectively stop the Corrosion cell (electron movement on the surface of the metal) so that Corrosion is halted. If the package is opened for inspection of parts, or for any other reason, some of the VCI Vapors will escape. At that point, the VCI again begins to outgas from the substrate until the air is once again VCI-rich. In addition, the VCI molecules are attracted to the surface of the metal due to their polarity. This enables the molecules to form a strong bond with the metal surface. This molecular layer is only 1-3 molecules thick, but it is sufficiently strong to prevent Moisture and Oxygen from reaching the surface of the metal, so it will remain Corrosion-free. Higher temperatures and higher levels of Humidity in the air actually increase the effectiveness of VCI. High temperatures act as a catalyst, making the VCI Molecules Vaporize more quickly. Likewise, Higher Humidity enables the ions to disassociate more quickly, and re-associate as they form a bond on the surface of the metal. As Temperature increases, the Vapor pressure of the VCI also increases, so the VCI chemistry is at a higher concentration in warmer temperatures, just when you need them the most. Thus, the higher the Temperature, and the higher the Humidity, the more quickly and effectively VCI Products will perform in Corrosion Prevention. For More Information; www.benzvci.com www.benz-packaging.com