According to the definition of European standard EN10346-2015, zinc-aluminum-magnesium coating is a ternary alloy coating whose main component is zinc, and the content of aluminum and magnesium is between 1.5 and 8% (of which the magnesium content is not less than 0.2%).
Compared with traditional coatings such as hot-dip galvanizing, galvanized aluminum, and zinc-iron alloys, zinc-aluminum-magnesium coatings have better corrosion resistance.
Advantages of zinc, aluminum and magnesium products
1.Super corrosion-resistant
Al, Mg, Si and other alloying elements are added to the zinc-aluminum-magnesium steel plate coating, which greatly improves the corrosion inhibition effect of the coating. Compared with ordinary galvanized products, the coating has less adhesion but can achieve better corrosion resistance. It is a hot-dip 10 to 20 times that of galvanized steel plate.
2.Self-healing
The self-healing of the processing incisions of zinc, aluminum and magnesium products means that in a humid corrosive environment on the incision surface, the coating material near the incisions dissolves into the water film attached to the surface of the exposed metal and continuously migrates and dissipates to the exposed incisions, forming a mixture of zinc hydroxide, A dense protective film (white rust) composed of alkaline zinc chloride and magnesium hydroxide gradually covers the exposed cut metal, separating the external corrosive medium from the exposed metal matrix, thereby preventing further corrosion of the exposed cut. The whole process will take a long time.
3.Long life
The key component of zinc, aluminum and magnesium is the addition of Mg-Al-Zn, which has strong and reliable resistance to chlorine (edible salt/sweat stains/sea surface/night breeze/soil layer) and alkali corrosion resistance, which can ensure that it will not occur for 20-30 years. red rust.
This is a coating product with excellent comprehensive performance. It can be 10-20 times stronger than zinc plating at the same coating amount. It has excellent protection for the cut-off and has good welding performance.
The role of Mg and Al in zinc, aluminum and magnesium
▶ The Mg and Al in the zinc-aluminum-magnesium coating can stabilize basic zinc carbonate and prevent the formation of loose ZnO. It will promote the development of oxide corrosion products toward density, low solubility, and poor conductivity.
▶ When the AL content is high, dense precipitate corrosion products with good adhesion and low conductivity are generated.
▶ The polarization resistance of Zn-Al-Mg alloy coating is about twice that of pure zinc coating, which is one of the reasons why the corrosion resistance of Zn-Al-Mg alloy coating is higher than that of pure zinc
