What kind of technology is the anti-corrosion Dacromet process?

For the anti-corrosion Dacromet process, we have been introducing some advantages of this process. Some friends may also be more curious. What kind of mechanism does this new anti-corrosion technology achieve the purpose of anti-corrosion?
　　1. Anti-corrosion mechanism of Dacromet plating process
Since the Dacromet process is very complicated, we will just briefly talk about the anti-corrosion mechanism of the process here:
1. Mechanical shielding effect: The coating can form a dense protective film, reducing the gap between the coating and the metal substrate, so it has a certain mechanical barrier effect.
2. Self-passivation: The active metal flakes in the coating can form a passivation film through chemical interaction with chromic acid to achieve anti-corrosion effect.
3, Sacrificial anode electrochemical protection.

　　2. The current limitations of the Dacromet process
Since this technology was first invented and applied by developed countries, the current domestic Dacromet plating process still has certain technical limitations, which limits its application in automotive anticorrosion. For example, at present, the cost of Dacromet treatment It is still higher than that of galvanized treatment, which is one of the main reasons affecting the large-scale application of Dacromet technology in automobile anticorrosion.
In addition, parts treated by Dacromet process can be connected with aluminum parts, but in the assembly with stainless steel, magnesium, copper and nickel, contact corrosion will occur; Dacromet coating has low hardness and poor wear resistance. Not suitable for moving parts and parts used in high wear-resistant occasions.