The principle of Dacromet's surface treatment is to isolate the interaction between water, oxygen and iron to obtain a strong anti-corrosion effect. The principle is mainly the cooperation of three protective pathways.
Barrier effect: The flaky zinc and aluminum layers in the coating overlap on the surface of the steel to form a protective layer, which hinders the corrosive medium such as water and oxygen from contacting the substrate, which has a relatively direct isolation effect.
Passivation: In the process of coating treatment of chromic acid with zinc, aluminum powder and base metal Dacromet, the passivation film formed on the surface by chemical reaction, the passivation film is not prone to corrosion reaction, and also acts as a barrier. The action of corrosive media, together with the barrier effect, provides a two-layer defense that reinforces the effects of physical isolation.
Cathodic protection: This is an important protective effect. As with the principle of galvanized layer, cathodic protection is applied to the substrate at the chemical layer by sacrificing the anode.
These three kinds of protection prevent the corrosive effect of the corrosive medium on the steel, and on the other hand, the substrate is electrically corroded. It is no wonder that there are several times the protection effect of the traditional electroplating zinc.
