Black Oxide Steel Parts

Surface finish is the last step of metal injection molding, it is not a necessary but very important processing. Surface finish includes electroplating, anodize, electroforming, sandblasting, polishing, electrophoresis etc. In this article we are going to introduce Black oxide, which is a very common surface treatment for gun parts.

Black oxide is a kind of commonly used method of chemical surface treatment. The principle is to make the metal surface to produce a layer of oxide film, to isolate the air and attain purpose of rust protection. Black oxide can be adopted when cosmetic requirements is not high, the black finish steel parts is sometimes called blue.

The process of black oxide is as following:
1) Rinse
2) Degreasing: Workpiece must be completely immersed in the degreaser; Degreasing solution concentration PH value
12-14, processing time is 10 to 30 min, every 3-5 minutes shaking up and down several times, when the solution
concentration is lower than PH 12 replenish the degreasing powder;
3) Water cleaning
4) Pickling：Concentration of the pickling solution PH 2 to 4, the handling time is 5-10 min
5) Water cleaning
6) Black oxide: pool solution concentration PH 2.5 ~ 3.5, processing time 10-12 min;
7) Water cleaning
8) Blow-dry
9) Oiling