Custom steel
blackening.

What is black oxide coating

Black oxide coating is a chemical conversion treatment for steel surfaces that creates a thin dark layer. Unlike paint or thicker galvanic coatings, it changes part dimensions only minimally, which is why it is used for precision components.

Typical examples include screws, bushings, clamping elements, tool parts, levers, and machine components where a black technical appearance and basic corrosion protection are desired.

The conversion layer itself is not a strong barrier protection. Therefore, the surface is usually preserved with oil or wax after the process, and the resulting durability also depends on storage, handling, and the operating environment.

Appearance is influenced by the material, heat treatment, and surface condition before processing. Parts must be clean and free of scale; machining marks remain visible under the thin layer.

If a part is intended to operate in a humid exterior or aggressive environment, we will assess a more suitable protection. We can include blackening in a single delivery following machining and heat treatment.