Black Oxide Surface Finish for CNC Machining

Principle

Black oxide is a common chemical surface finish, after oxide, there will be a layer of oxide film on the metal product surface, in order to isolate the air, to achieve the purpose of rust. The surface finish is mainly used for steel component.

Common Method of Black Oxide

The common methods of black oxide are traditional alkaline heating black oxide and at room temperature black oxide. But the effect of black oxide at room temperature for the mild steel is not very good. For traditional alkaline heating black oxide, it is divided into one-time black oxide and twice black oxide.

And the main components of black oxide liquor are sodium hydroxide and sodium nitrite.

Processing Step

Clamping Workpiece → Oil Removal → Washing → Pickling → Washing → Oxide → Washing → Saponification →  Boiling and Washing → inspection.

Function

– After black oxide, it will be with better effect of outlook.

– After black oxide, there will be with oxidation film on the surface of the metal part, it will be isolated water and air from the metal products. So that improves the anti-rust performance of the metal products.

– After black oxide, there will be oxide film produced on the surface, that increases the wear resistance, thus prolonging the service life of the metal product.