De-icing chemicals: A growing threat

Motor vehicles face a constant battle against the elements, with one of the most insidious threats being corrosion. In colder climates where snow and ice are prevalent, it’s not uncommon to see traditional road salt (NaCl) being used on the roadways to expedite the melting process. In recent years, another chemical compound has been added to the mix to help combat snow and ice, magnesium chloride (MgC₂). Magnesium chloride, typically applied as a pre-treatment of roadways in liquid form and often included in different brine concoctions, is more effective than traditional salt because it can work in lower temperatures, it is also up to 13 times more corrosive to automobile components*. Magnesium chloride is also used during the non-winter months for dust control on gravel and dirt roads.

The science of corrosion

The process of rust corrosion is an electrochemical reaction between an anode, cathode and an electrolyte. The metal in your vehicle acts as both the anode and cathode portion of the reaction, while water and oxygen typically provide the electrolyte portion. Rust as iron oxide is a molecule containing two iron atoms and three oxygen atoms. The electrochemical reaction occurs when the anode portion of the metal releases electrons, and the cathode portion of the metal accepts the electrons, in this case iron, which can corrode and weaken. This process is exacerbated when road salts, like sodium chloride or magnesium chloride, encounter metal surfaces.

When salt is applied to roads, it dissolves in the presence of moisture and creates a conductive solution that accelerates the electrochemical reactions responsible for corrosion. Magnesium chloride is known to be even more aggressive than traditional road salt because it’s hygroscopic, meaning that it attracts moisture from the air, essentially reactivating itself in as little as 25% humidity. This increases the time metal components are exposed to corrosive conditions, even in dry weather, promoting faster rusting.

The areas of concern

Corrosion typically begins in areas where water and salt and/or Magnesium Chloride have the highest likelihood of accumulating. This includes parts of the vehicle like the undercarriage, wheel wells, brake lines and frame. Not to mention the inner cavities of the vehicle, which are highly susceptible as well as the inside of the frame, crossmembers, rocker panels and doors. Even though you may regularly clean the salt and magnesium chloride off the exterior surfaces, it remains inside the inner cavities of the vehicle.

The impact of rust

While the aesthetic effects of corrosion, such as visible rust spots, are bad enough. The real danger lies in the deterioration of critical components, such as brake lines and suspension parts, due to corrosion. In some cases, this damage can go unnoticed until it leads to a catastrophic failure, putting the safety of the driver and other motorists at risk. Severe corrosion of the frame can compromise the overall structural integrity of the vehicle, including the vehicle’s ability to absorb crash impacts. This can have dire consequences in the event of a collision. Besides the major safety concerns that corrosion presents, it also results in accelerated wear and high maintenance/repair cost. Not to mention the financial burden associated with the vehicle being in a repair facility instead of on the road. The Federal Highway Administration estimates corrosion cost to the nation’s transportation industry at more than $30 Billion annually.

The solution

Despite the inevitability of exposure to road salt, magnesium chloride and other de-icing chemicals, several strategies can help reduce the risk of corrosion and prolong the lifespan of a vehicle.

• Regular washing: One of the simplest and easy ways to combat corrosion is to regularly wash the undercarriage of the vehicle. Removing salt and magnesium chloride buildup can minimize exposure to these corrosive agents.
• Undercoating and “rust proofing”: Undercoating is an excellent preventive measure to help combat the effects of road salt and magnesium chloride, by providing a protective barrier to the undercarriage of the vehicle.

However, when it comes to that last bullet point, not all undercoatings are the same and provide maximum protection. Take, for instance, a rubberized undercoat; initially, it will protect the metal substrate, but after repeated exposure to extreme cold/hot temperatures, it will become brittle and will crack and peel allowing moisture and the very chemicals that we’re trying to avoid to get behind the coating and start corroding.

Another example in the market is an oiling process that typically uses lanolin-based products. This process will also initially provide some protection. However, one downside is that these oiling products must be reapplied multiple times a year because of its ability to be washed partially off, which will increase your maintenance cost and make a mess of your facility in the process. Additionally, these products don’t fully dry or cure, which will attract road grime and the aggressive de-icing chemicals. The only tried-and-true solution is an asphalt cutback-based undercoating paired with a Cavity Rust Inhibitor.

VALUGARD coatings by Automotive International are formulated using highly refined resins and multiple corrosion inhibitors, providing unmatched protection against rust. VALUGARD coatings have passed and exceeded rigorous anticorrosion testing (ASTMB117, SAE-J2334, NACETM-01-69) and have been analyzed, assessed and approved by some of the world’s most prestigious automotive manufacturers, including being featured in numerous OEM corrosion technical service bulletins and recalls as a solution to their problem.

The first step in the VALUGARD rust prevention process is the application of the cavity rust inhibitor, which is jet atomized and fogged into all the inner cavities of the vehicle (inner frame/cross members, doors, rocker panels, fenders, tailgate, etc.). This is a noninvasive process, using the existing drainage holes with no drilling required. This product will creep into the inner nooks and crannies to protect the vehicle from rusting from the inside out. The VALUGARD cavity rust inhibitor also holds the dielectric strength and will help to protect wiring and other electrical components that are often hidden inside these panels from corroding.

Step two is the application of the asphalt cutback-based undercoating, which is applied to the undercarriage of the vehicle (exterior frame, sheet metal, inside wheel wells). While considered a soft coating, it will be dry to the touch after it cures, but will also remain flexible to change with the climate and the flex of the vehicle. It is also considered a self-healing coating. For instance, if an extremely hard rock impact were to scribe the coating, the self-healing properties will not allow moisture or de-icing chemicals to undercut the coating and form corrosion. In addition, both the undercoating and the cavity rust inhibitor provide a protective barrier against galvanic corrosion between dissimilar metals that are becoming more commonly used in the vehicle manufacturing process. VALUGARD protective coatings are designed for a onetime application, though some heavily used vehicles or ones exposed to constant harsh environments may require additional touch-ups on certain areas.

In conclusion

Road salt and magnesium chloride use has undeniably improved winter road safety by preventing ice buildup and improving traction. However, these chemicals also introduce significant challenges for vehicle owners, primarily through the accelerated corrosion of automotive components. From weakened structural integrity to costly repairs, the effects of corrosion are far-reaching. Regular maintenance, inspections and protective coatings are essential to combat the damaging effects of road salt and magnesium chloride. By understanding these risks and taking proactive steps, you can significantly reduce the impact of corrosion and prolong the life of your vehicles. If you’re now a little less confident about your current vehicle corrosion protection program (or worse yet haven’t implemented one), visit our website at www.valugard.net for more information on how to stop rust!

*Source: Department of Transportation report, No. CDOT-DTD-R-2002-4, Corrosion Effects of Magnesium Chloride and Sodium Chloride on Automobile Components

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