The Science behind Rust and Corrosion

Road Salt (Sodium Chloride) – This compound is spread onto roads before and during a snow/ice storm when temperatures remain near freezing. However, it is harmful to your vehicle.

On steel, Sodium Chloride acts as an electrolyte. Electrolytes speed up the chemical reaction that occurs when iron or aluminum metal comes into contact with oxygen and water. This causes the metal to lose electrons more readily and thus accelerates the rusting process.

On aluminum, Sodium Chloride has chloride ions that disrupt the protective oxide layer that naturally forms on aluminum. This allows the metal to interact directly with the environment, leading to pitting corrosion. It is especially bad when the aluminum is exposed to moisture. In other words, the chloride ions "attack" the oxide layer, creating weak spots where corrosion can begin.

Hydrochloride (HCl) (Liquid Brine) is painted onto the road before a storm, where it dries and lays dormant until activated with rain or snow. It is also known as hydrochloric acid and it causes rust or corrosion.

On steel, Hydrochloride readily reacts with iron, breaking down its protective oxide layer and forming iron chloride. Iron chloride readily oxidizes in the presence of oxygen and moisture, leading to the formation of rust on the metal surface. Hydrochloride is far more harmful to your vehicle than salt.

On Aluminum, Hydrochloride readily breaks down the protective oxide layer that naturally forms on the aluminum surface, allowing the aluminum metal to directly react with the acidic hydrogen ions (H+) in the solution. This leads to the

formation of aluminum chloride and the release of hydrogen gas. The process is further accelerated by the presence of chloride ions, which can penetrate the oxide layer and initiate localized corrosion. This is often referred to as pitting corrosion.

These two chemicals get inside your vehicle’s panels as you drive on the road. They enter from inside your windows into your door panels or spray upwards into your vehicle’s body panels and undercarriage. Although salt is relatively easy to remove in a car wash, Hydrochloride isn’t. It is designed to stay in place. And once it attaches itself to the inside of your vehicle, it continuously attacks your metal body parts.