New for 2016: ECO is FFL (Federal Firearm Licensee)
ECO Finishing Company

Zinc Plating

Anodizing Aluminum

Nickel Plating

Electroless Nickel

Copper Plating


Black Oxide

Phosphate Coating

Hard Coat Anodization

Chemical Conversion Coatings

RoHS/REACH Compliance

Black Oxide Coating at ECO Finishing

ECO Finishing provides Black Oxide coating services in Minneapolis that are compliant with MIL-DTL- 3924. With over 60,000 sq ft of clean, well lit space, ECO Finishing has a streamlined process that complies with all EPA regulations regarding safety and waste treatment.

The Black Oxide coating process was developed in the early 1900's and the chemical process has changed little since. Black Oxide is a chemical conversion coating process, and as such does not change the dimensional properties of the coated part. When a part is coated with Black Oxide, the chemical conversion process converts the iron to the naturally occurring black iron oxide compound called magnetite. The coating becomes an integral part of the base metal and does not chip, peel, crack or rub off. Further, the coating is resistant to bending and flexing of the base metal. Black Oxide has limited corrosion protection.

Black Oxide can be used to coat mild steel, stainless steel, brass, bronze, copper, zinc and powdered metals. There are four classes of Black Oxide coating, including:
  • Class 1 Alkaline oxidizing process for wrought, cast and malleable irons, plain carbon and low alloy steel
  • Class 2 Alkaline chromate oxidizing process for certain corrosion resistant steel alloys which are tempered to 900 degrees F or higher. Coating shalled be formed from a boiling alkaline chromate oxidizing solution.
  • Class 3 Fused salt oxidizing process for corrosion resistant steel alloys which are tempered to 900 degrees F or higher. After immersion parts are withdrawn, cooled for eight to ten minutes and rinsed in hot water.
  • Class 4 Alkaline oxidizing process for other corrosion resistant steel alloys. Salt spray test per ASTM-B117 prior to application of a preservative.
Class 1,2 and 3 need to pass an "oxalic acid spot test" prior to the application of a preservative. All classes need to pass the "smut test" after coating and before application of corrosion preservative compound.

ECO Finishing provides Black Oxide services to a wide range of industries including automotive, aerospace, medical, military and manufacturers of industrial and consumer products. Our Black Oxide coating tank is 5' x 3' x 3' allowing us to coat both large and small parts.

Quality is at the heart of ECO Finishing. Each job is carefully monitored from its arrival through the entire plating process. Inspection of plated parts is enhanced by more than 100 foot candles of light throughout the entire plant. Zinc plated thickness measurements are verified with X-ray fluorescence and our quality system conforms to military specifications as outlined in MIL-Q-45208. ECO uses Statistical Process Control (SPC) to assure that our product meets exacting industry standards.

ECO Finishing has the fastest lead time of any metal finishing company in Minnesota. We can process within hours, within a day or on your schedule. Our average turn time is two to three days. The goal is to support our customers as they grow their business by beating their competition.

At ECO Finishing, we believe that our job is to make your life easier! We specialize in Just in Time (JIT) deliveries and fast turnaround orders. We are known by our customers for our commitment and dedication to quality. ECO has the history, experience and professionalism to be sure to make your job easier. Contact ECO Finishing today for Black Oxide at (763) 574-1000.