How Chromate Conversion or Alodine Coating Works on Aluminum

chem film coating
December 12, 2022

Spending billions on corrosion solutions is a cost that companies want to avoid. Alodine coating is one solution that can help to limit the chance that businesses will have to contribute to what the manufacturing industry spends annually on fixing corrosion-related problems. To expect to spend this much on what wasn’t planned can take a toll on a business’s financial resources.

The manufacturing industry spends billions each year fixing and replacing corroded machinery and other forms of equipment. Different metals corrode at different rates. If you consider steel, if it’s already located in a highly acidic environment, you can expect higher rates of corrosion.

If that steel is in the harsh or aggressive ground, you could expect corrosion to take place by 20 microns each year or even more. Aggressive ground doesn’t have pH levels that are too favorable, leaving them more susceptible to exposure to faster corrosion.

Aside from simple equipment location, some tools and even buildings will have some risk of excessive corrosion development. This leaves companies wondering what interventions can be used to deflect these issues. Keep reading as we talk more about a key intervention to prevent the corrosion of your equipment.

What Should You Know About Chromate Conversion?

The coating itself is only about 0.00001 to 0.00004 inches in thickness. This means it can keep the weight as is without altering the weight of the equipment. The significance of this chemical is that it’s able to provide an extra protective layer to your equipment.

This is what’s referred to as passivating or passivation. While it works to protect the surface of your equipment as a coating, it can also work as a base coat.

Using this as a primer is a good way to apply chromate conversion. This is because it will provide additional layers of protectant and can withstand a variety of environments.

How Does Chromate Conversion Coating Work?

The chromate conversion coating goes through a chemical reaction with the base metal to create a barrier. This barrier is resistant to external chemicals and water. The chromate conversion coating is often used for things like small parts, machine tools, and marine equipment.

It can be applied to more than just aluminum alloys. It can work with zinc, magnesium, as well as cadmium, and other metals. The coating itself is very thin. It’s designed to protect the metal from corrosion without adding a lot of weight to the equipment.

Keep in mind that a chromate conversion coating is applied to aluminum that has already been anodized. While this is true, some conversion coatings will not help with binding to organic coating if you’re trying to improve paint adherence, etc.

Chromate conversion is applied through a process called plating, and a plating solution is applied to the equipment. The solution contains chromium and other chemicals that help with the plating process. The chemicals in the solution interact with the metal and this is what creates a new coating.

Alodine Coating: What Exactly Is It and What Is It Used For?

So, what is alodine? Alodine is a type of chromate conversion coating that can be applied to aluminum along with a variety of other metals that need to be protected from corrosion.

You might refer to his type of coating as Chem Film or chem film. One of the most notable factors of this coating is that It has a higher corrosion resistance than an aluminum oxide coating.

Alodine is used in a lot of applications and can be used for electrical components, and offers electrical and thermal conductivity. Alodine can also be used to help increase the durability of electrical circuitry through the electrical conductivity the coating offers.

The Benefits of Alodine Coating

Alodine is a good way to protect aluminum alloys and reduce signs of preventable corrosion and wear. When alodining your equipment, that coating of the chemical will harden, and it can last for years. Not only does it extend the lifespan of equipment, but the chemical itself will have long-lasting effects for an extended amount of time.

In most cases, a reapplication won’t be necessary for a few years. Let’s take a look at some of the other clear advantages you can expect when using alodine coating.

Improved Corrosion Resistance

Alodine coating provides better corrosion resistance than some alternatives. While immersion time only takes a few minutes, this is a sufficient enough amount of time to protect your equipment.

Added Benefit Without Sacrificing Results

Alodine protects the parts that you apply it to but after application, it doesn’t add any additional weight to the part. Also, after you treat something with this chemical, minor damages such as scuffs or scratches won’t compromise the capability of the part. It will remain effective against corrosion.

Cost Effective Solution

Alodine coating is one of the most cost-effective options. It lasts long, is durable, and won’t compromise the integrity of the parts you apply it to.

Better Electrical Conductivity

Alodine coating is actually a conductor. This just means that it’s electrically conducted. A transparent form of passivation can provide a great level of electrical resistance. This is possible through protective layers.


The resistance it can provide will often go up to 500 microOhms. There are also other versions that could be used, such as Alodine 1200S to accommodate more resistance.

Improvement in paint Adhesion

Because alodine coating provides better corrosion resistance, it can also help to strengthen the integrity of the equipment’s surface. This makes paint adhesion more efficient.

Enhancing the Performance and Life of Your Equipment

Corrosion is often the culprit of damaged equipment. It can affect the performance levels of things companies need to operate efficiently. Alodine coating helps to prevent these issues while extending the life of your tools and machinery, making it more possible to enhance your operations.

Working with NAMF gives you access to an experienced build-to-print manufacturer. Operating since 1979, we provide high-quality materials while ensuring high-quality solutions. Reach out to our team to get started with your project today.