• Phone: (262) 782-2223
  • Fax: (262) 782-8775
  • 15955 West Overland Drive, New Berlin, WI 53151

Black Oxide Finishing

Large and Small Production

View Our Solutions

Stainless Steel Black Oxide

Dedicated to the Highest Quality Standards

Get a Quote

Class-1 and Class-4 Processes

Including Rack and Barrel Processing

Contact Us Now

Black Oxide Finishing

For Midwestern Manufacturing, Tool & Die, Automotive and Stamping Industries

UNICO provides black oxide finishing on a wide variety of parts. We can handle any size or configuration. Parts up to 60 inches long are processed in 1 cycle. Parts up to 100 inches long can be double dipped. (This creates a blur line on the part being processed.) We stand behind our workmanship, with over 95 years of combined processing experience.

What is Black Oxide?

Black oxide is a conversion coating formed by a chemical reaction produced when parts are immersed in the alkaline aqueous salt solution operated at approximately 285 degrees F. The reaction between the iron of the ferrous alloy and the hot oxide bath produces magnetite (Fe o4) on the actual surface of the part. It is possible to oxidize non-ferrous metals under suitable conditions to form black oxides. It is possible to apply black oxide at room temperature however it is not possible to achieve all of the benefits available from the “hot” oxide process. The cold black oxide process routinely shows color variation from part to part and the black material frequently rubs off in your hands. The cold process does not meet military or automotive specifications. Therefore, the remainder of this article addresses the “hot” black oxide process.

Why choose Unico?

  • We conform to military and industry standards
  • Fast turn around time
  • Competitive pricing
  • Large and small production
  • Rack and Barrel processing
  • Quick response to customers

UNICO is ready to assist you with your black oxide finishing needs. Contact us now at (262) 782-2223 to get started.

To ALL Unico customers,

We will be open to service your needs during this pandemic time period.

We will do all we can to keep the supply chain running with as little disruption as possible.

With that in mind, we ask that you ensure that your drivers or delivery persons have their own pens to sign paperwork as needed. Our employees have been instructed to use their own pens also so as to restrict the spread of as many germs as possible.

Please be safe and may this end soon.

Thanks for your help,

Douglas A. Sleaford
President and CEO
Unico of New Berlin
Unico of Milwaukee

What We Offer


Uniform coating for ferrous metals.


Decorative coatings and corrosion protection.


For moving parts that cannot tolerate the dimensional change of a more corrosion-resistant finish.


An alkaline oxidizing finish for 300 Series corrosion resistant alloys.

“Great work. I have been working with Unico for 20 plus years!”
– Dawn K.