Study on Al Coating and Black Passive Film on Steel Surface

Abstract

An Al coating and black passive film technique was developed in this research. Meanwhile, a fine and uniform Al coating with good binding force on steel surface was prepared. And a black passive film was used as a post-treated film of the electroplated Al coating. The result proves that the corrosion resistance of electroplated Al coating was over one time higher than that of zinc coating by black passivation. Besides, Al coating was less brittle with good ductility and, it could be used as a pretreatment layer before conducting laser heat treatment to significantly improve the efficiency of laser heat treatment.