Precision Part Specialists

Black Oxide Coating

Blackened finish following black oxide process

Peters’ black oxide process is alkaline in nature and is compatible with ferrous metals, tool steels, and powdered metals. The black oxide appearance is an attractive black surface (shiny or matt depending on the original surface condition of the component) that adds a mild corrosion resistance as well as minimizes light reflection. The finish will not chip, peal, or flake off. It can only be removed mechanically (sandblasted) or chemically.

Other industry and trade names for Black Oxide include Blackening, Black Passivating, Black Magic, Black N, Gun Bluing, and Black Penetrate.


  • Black Oxide MIL-DTL-13924 (Class 1 & Class 4)
  • Stainless Steel Black Oxide


  • 22W” x 22H” x 36L”, up to 39″ single dip, 78″ double dip

Since 1982, PHT has provided top quality black oxide. While inhibiting rust and improving salt spray results, customers also use our black oxide to enhance the appearance of their tools and fixtures.

Our system maintenance frequencies provide a clean system hygiene that provides the ultimate in the deep black our customers have come to expect.

There are several items that you can watch to optimize your black oxide quality:

  1. Machined or media blasted surfaces produce the deepest blacks.   We do employ acid activation for those surfaces that cannot be machined or blasted but we use our acid activation cautiously with individual customer needs in mind.
  2. EDM surfaces: the recast layers may inhibit effective black oxide results and may need to be activated.
  3. Heavy oil, grease, mill scale, or heavy rust will need to be removed for best quality black oxide.
  4. Tell us the grade of material you are presenting. High chromium content does resist the blackening process. By telling us what your material grade is we can alter our process to optimize your result.

Applications include:

  • Firearms
  • Fixturing
  • Gears
  • Molds
  • Pins
  • Tooling Components


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