One of the most common reasons people choose a black oxide finish for their machined parts is its aesthetic appeal. In fact, black oxide is especially recognized for creating a clean, uniform, and deep black surface.
But did you know that this treatment, sometimes called “blackening” or “chemical burnishing”, offers more than just visual benefits? It can also improve the durability of metal parts that receive it:
- Screws, bolts, nuts
- Gears
- Mechanical and hydraulic parts
- Hand tools
- And many more.
In this article, our surface treatment specialists highlight the key benefits of black oxidation for extending the longevity of metal parts.
1 – Enhanced Corrosion Resistance
Through a chemical reaction, black oxidation treatment forms a protective layer on the metal surface. This extremely thin layer, generally composed of stable metal oxides, acts as a physical barrier between the metal and the external environment. By shielding the metal from moisture, air and other corrosive agents that may be present in industrial environments, it effectively helps to prevent corrosion.
For optimal corrosion protection, we recommend sealing the black oxide layer with a sealant to close any pores. Various oils or waxes can be used for this purpose.
2 – Better Wear Resistance
The oxide layer produced by the burnishing process also provides some resistance to wear and abrasion, which helps extend the life of the machined parts. It does not flake off easily and, in some applications, is harder than the substrate.
This increased hardness allows treated parts to better handle abrasive materials when subjected to friction.
In addition, the black oxide topcoat won’t be removed by temperature changes, so it can be exposed to intense heat or cold without risk of damage.
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3 – Greater Ease of Maintenance
One of the keys to maximizing the life of metal parts is regular maintenance. Black oxide finished components are easier to clean because you don’t have to worry about tarnishing them with even the strongest cleaning products.
In fact, this finish will not flake off because it can only be removed mechanically or chemically, not with water or detergents.
4 – Better Lubrication
The surface of black oxide is relatively porous, which means it absorbs and retains the sealant (often oil) after finishing. This offers the advantage of providing better lubrication between moving parts than other surface finishes.
This property notably reduces the risk of frictional wear on treated components.
Other Significant Advantages
Dimensional Stability
Due to the formation of black oxide on the surface, there is a slight increase in the size of parts that are blackened. However, this increase is minimal compared to other processes such as painting and galvanizing.
The black oxide layer is typically one to two microns thick, which is almost negligible and, in most cases, does not affect functionality. This makes the process suitable for close tolerance parts.
Compatibility with Welding
Parts treated with black oxidation can be subjected to various types of welding without concern of generating harmful fumes.
Reduced Light Reflection
A glossy or matte appearance can be achieved by selecting the appropriate post-treatment sealant.
For example, giving a part a matte finish minimizes light reflection, which can be a critical property in many applications (like in UV and IR sensors and detectors).
Affordable Price
Despite all its benefits, black oxide is generally less expensive than electroplating or powder coating.
Enjoy the Benefits of Black Oxide Coating
In short, black oxide coating offers more than just aesthetic benefits. In fact, the pleasing appearance it gives to metal parts is just the tip of the iceberg!
At Omnifab, we’ve long recognized these advantages and that’s why we don’t hesitate to offer our customers the option of burnishing their steel, low-alloy steel or copper parts to guarantee their satisfaction.
Please contact us for a quote or to learn more about our black oxide coating services.
