Black Oxide Coating (Chemical Blackening)
Black oxide (chemical blackening) is a chemical conversion coating that gives metals a matte black appearance and dimensional stability. When oiled, metals with this coating can provide corrosion resistance. Chemical conversion coatings are generally completed by subjecting the surface of a metal to a chemical or electrochemical process, and black oxide coating is one of them.
AMS 2485, MIL-C-13924 and MIL-DTL-13924 We apply black oxide coating in accordance with these standards.
Black Oxide Process
- Cleaning: oil, rust and contaminants are removed.
- Activation: the surface is prepared for the blackening bath.
- Black oxide bath: a black iron oxide layer forms on the steel surface.
- Rinsing and post-treatment: oil or a similar protective is applied to improve corrosion resistance.
Properties
- It has practically no effect on dimensions; it is suitable for threaded, press-fit and tight-tolerance parts.
- It provides a matte black, low-reflection appearance.
- Corrosion resistance depends largely on the final oiling; it gives the best results for indoor use and parts operating in oil. For outdoor use and high corrosion risk, powder coating or wet painting should be considered.
Typical Applications
Fasteners, hand tools, machine and fixture parts, and mechanism parts in the defense industry. Suitable materials are generally carbon steels and low-alloy steels; we recommend specifying your material at the quotation stage.
You can specify the standard and class in your technical drawing (e.g. MIL-DTL-13924 or AMS 2485). For writing the coating note, see our coating guide for designers (in Turkish) .
Related services: At our facility in Ankara İvedik OSB we also offer stainless steel passivation and sandblasting services. You can send the technical drawing of your part via our quote form .