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Black Oxide Coating

We deliver smooth, long-lasting protection for firearms, automotive parts, hand tools, and more.

Flawless Finishing That Lasts

Black oxide coating (also known as blackening, oxidizing, oxiding, black passivating, and gun bluing) gives visual appeal, reduces reflectivity, and slightly enhances corrosion resistance with minimal effect on your parts’ dimensions. 

What is Black Oxide Coating?

Black oxide coating creates a chemical reaction on the surface of a metal part that turns it black.

Why not just paint your parts black? Well, paint is a layer that makes your parts bigger by a few thousandths of an inch. In other words, the paint causes a dimensional change, and even small fluctuations can affect how different parts fit together. Black oxide treatment, by contrast, leaves parts essentially the same size because it’s only a few microns (millionths of a meter) thick.

So, black oxide gives you an attractive black finish and a modicum of corrosion resistance. Even better, you don’t have to buy any black paint or worry about the chipping, peeling or flaking of the finish.

That makes black oxide finishing a practical, economical way to give metal parts an attractive physical appearance. The process can also be used to reduce glare from a part in applications where that would be beneficial. This reduces glare and eye fatigue for the user.

How Black Oxide Coating Works

Black oxiding creates magnetite (Fe3O4), an alloy of iron and oxygen molecules, on the surface of the metal.

Dipping a metal part into a heated, alkaline liquid for a specific period of time triggers the chemical process that forms magnetite on the part’s surface.

Yes, that means black oxide is a kind of rust (it’s black instead of red). But it’s done under controlled circumstances that add corrosion resistance to the metal part instead of causing it to decay.

Applications for Black Oxide

Because black oxide is mainly for aesthetic appeal, it’s rarely used on parts most people never see. But metal parts people can see — and especially hold in their hands — may be good candidates for black oxide, which is common in:

  • Firearm components like barrels and stocks
  • Hand tools like wrenches and crowbars
  • Nuts, bolts, screws and washers in products people assemble themselves
  • Under-the-hood engine parts like pulleys and hood braces

There are many other applications for the black oxide process. If you want a product to have an aesthetically pleasing black exterior, black oxiding is one of the most practical ways to achieve that result.

Applications for Black Oxide

We use a rack-and-barrel approach to black oxide processing. This technique allows us to treat parts of nearly any size. The result is you get the attractive black finish you want without worrying about any of the performance issues that may arise with a paint finish.

With decades of experience in treating metal parts and computerized processes to ensure accuracy and hold costs down, we can ensure your parts meet the most demanding specifications and industry standards.

Bring Us Your Challenges

Do you need better results from your next black oxide coating project? Paulo can help. Tell us a little about your project to get connected with a Paulo expert.

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