Lincoln Industries

In the April Catalyst newsletter’s feature story, you can read about how we partnered with Schaeffler to provide a black oxide finish for one of their products. But what exactly is black oxide, and why would you want to use it?

Black oxide is a conversion coating formed through a chemical reaction when products are submerged in an alkaline aqueous salt solution at approximately 290 degrees F. A truly unique finish, black oxide has a number of advantages that make it ideal for certain applications.

No dimensional changes
Black oxide does not change the dimensional, physical, or mechanical properties of the treated surface. No metal is removed or deposited.

Highly abrasion-resistant
Unless mechanical or chemical means are used, black oxide cannot be removed through chipping, peeling, flaking, or rubbing.

Unique visual properties
Besides the unique black color of this finish (which can be shiny or matte depending on customer preference), black oxide finishes also reduce the light glare from reflections.

Improved lubricity
Parts that are black oxidized enjoy improved lubricity, which minimizes the heat buildup that can accelerate failure.

Open to supplemental treatment
Black oxide can easily be fitted with supplementary treatments (or “after-finishes”) that can further improve the appearance and resistance to abrasion and corrosion for the finished part.

Temperature-resistant
Black oxide finishes can typically be exposed to temperatures of 900 degrees F before the color begins to change.

The Lincoln Industries Difference
We have over 35 years experience working with black oxide. Though the black oxide finishing process itself has been around a long time, we’ve developed innovative enhancements that have helped improve the end product for our customers. For example, we are one of the few in the industry to offer rotating rack plating. Using this rotating rack design, parts are immersed individually and rotated, resulting in a more precise finish and eliminating rack marks. Rack marks are areas of the part that could not be finished because they were in contact with the rack when submerged. Since rotating racks expose the entire surface of the part, rack marks are not an issue.

Typically, black oxide finish is applied through barrel-plating, which we also offer. In this process, parts are submerged in a barrel, which may result in more part-on-part damage. This process is less expensive and ideal for products where aesthetics are less of an issue. In contrast, rotating rack plating is ideal for parts that are too large to fit in submersion tanks or when aesthetic issues and reduced part-on-part damage are important.

Wondering whether black oxide is right for you? We’ll work closely with you to determine if indeed black oxide is the way to go. For more questions or inquiries, please email us at sales@lincolnindustries.com.