Black Oxide Coating

For moving parts which cannot tolerate the dimensional change of a more corrosion resistant finish. For decorative applications and can be used to decrease light reflection.

A uniform black coating for ferrous metals. Mostly a decorative coating with limited corrosion protection under mild corrosion conditions.

Black oxide coatings should normally be given a post supplementary oil treatment.

MIL-C-13924

Class 1

Alkaline oxidizing for wrought iron, cast and malleable irons, plain carbon and low alloy steel.

Class 2

Alkaline-chromate oxidizing used on certain corrosion resistant steel alloys tempered at less than 900 deg F.

Class 3

Fused salt oxidizing for corrosion resistant steel alloys which are tempered at 900 deg For higher.