Black Oxide

Bronson Plating is a leader in black oxide coating, a conversion coating for ferrous materials. Black oxide is a great choice for minimal build-up, the ability to add mild corrosion resistance, and for its appearance.

In the process of applying black oxide coating, experts at Bronson Plating use a hot bath of primarily sodium hydroxide (caustic soda) to convert the surface of the material into magnetite. The caustic soda bonds chemically to the surface of the metal, creating a porous base layer on the part. To achieve maximum corrosion resistance, black oxide must be impregnated with oil. So, we then apply oil to the heated part, which seals the porous layer. It is the oil that prevents the corrosion of the work piece. Bronson Plating uses automated barrel equipment to process parts with black oxide.

No matter what process you require, we’ll turn most jobs around in less than one week, even if you lack a firm volume schedule or need flexibility in your supply base. Our employees are cross-trained to run multiple lines, and we have a dedicated scheduling department. We have great flexibility, a high capacity, and the ability to run jobs on multiple lines. We’ll flex our schedule to meet your demands, and we will follow up to ensure that your needs are met.


  • Blackening can be done in large batches (ideal for small parts)
  • No significant dimensional changes
  • Economical corrosion protection system