What is Road Salt Doing to my Vehicle?

January 20, 2016

It’s time for a lesson in oxidation and chemical reactions! Hooray! Who doesn’t love an exploratory and in depth look into why and how salt eats away at our vehicles? Without diving too deep into the pits of our high school chemistry mental notes and study guides, we hope to explain as thoroughly as we can the science behind rust and how salt impacts the process. We’re ready to start the lesson!

Corrosion 101 -

Rust happens naturally. It is always going to happen and will always happen. It’s nature’s way of correcting things and removing solid substances from our existence. Chemists refer to rusting as a type of corrosion. Corrosion is the process by which something deteriorates because of oxidization.[1] Thanks to the abundance of elements found on Earth, there is ample opportunity for various elements to find each other and ultimately form chemical reactions. When oxygen from the atmosphere or from moisture, typically water, is introduced to the metals in our vehicles, we are left with rust. Corrosion is the process and oxidation is the result.

So how does salt aid in the rusting process? -

If there was ever a truer love story than oxygen and iron, we would love to see it. These two elements in almost every chemical reaction seek each other out and bond. Oxygen is found naturally in the air we breathe so finding a pure form of iron is a daunting task. Even in the driest, warmest of climates, oxygen is still giving up electrons and iron is still gladly accepting them. Now imagine being in the northern states, near water, where the roads are salted because of snow. It’s where oxygen and iron would settle down to raise a family in their love story!

Sodium chloride, or salt, is an effective way of removing snow and ice from our roads at a low cost. Municipalities spread both salt and sand on our roads to help with traction, but there are other varieties of road salt that distribute more ions when they dissolve in water. Those free floating ions work to reduce the freezing point of water – in sodium chloride’s case, down to about 15 degrees Fahrenheit in real-world conditions. So when road salt does its job, it’s introducing a lot of free floating ions into melting water on the road, just waiting for your tires to come along and kick up some ion-filled road spray into your wheel-wells and other moisture-trapping crevices.[2] This is the one time you should be glad your county or city is cheap because the other varieties of road salt do much more damage to your vehicle!

The salt on your vehicle lowers the freezing temperature of water and allows for moisture to accumulate on your vehicle. Being that the metal in your vehicle consists of mostly iron, salt allows for oxygen to continue the corrosion process. Then once the rust starts, it works quickly. Iron oxide molecules take up more space than iron atoms, so they start to expand. Carbon dioxide in the water combines with the iron to create iron hydroxide, another form of rust that easily separates from the base metal. None of these processes stop unless all the corrosion is removed and the base metal is protected by some form of barrier.

Protected by some type of barrier, eh? If only there was some magical place you could go to for such a barrier. A place, we’d like to imagine, that has been in business for 50+ years and made its name in rust protection. A place that is the industry leader in automotive protection and detailing services.

A place that’s only one click away!


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