subject: The Application Characteristics Of Zinc And Zinc Alloys [print this page] Zinc is a silvery-white metal, with a metallic luster. Melting point of 419 degrees Celsius, density 7.14g/cm3, standard electrode potential of-0.76V, is one of the more reactive metal. Zinc for the close-packed hexagonal crystal structure, with increasing temperature, showing that changes with heterogeneous elements.
The appearance of dark white zinc coating, the coating density is generally 6.27g/cm3, thermal spraying is the use of anti-corrosion construction of the first, and most of the coating material. However, sulfur or zinc oxide air pollution does not have a corrosion resistance coating. Although the passivation of zinc with a small, Nickel oxide but significant chromate passivation solution was able to produce zinc chromate protective film.
Thermal spraying of zinc raw material requirements with high purity, corrosion when the purity requirement Zn99.995% with more than 0.001% iron in the following. As a zinc wire at least 99.9% purity, Cu0.05% or less, in order to prevent the spray break, Zinc oxide tensile strength greater than required 150Mpa, elongation greater than 40% ultra-high purity, the more small spray particles, coating the surface of the more dense.
Thermal spraying of zinc-aluminum alloy is mainly used with AI amount of 5% to 25% of the zinc-aluminum binary alloy. When the alloy aluminum content greater than 28%, the alloy with many chemical and electrochemical properties similar to aluminum, thermal spray corrosion if used, Titanium dioxide you can not very well how to play the role of cathodic protection. On the other hand, due to increased aluminum alloy in the alloy wire down to processing difficulties, it is currently used 85% of zinc, aluminum content of 15% of the binary Zn-Al alloy. The common alloy grades for the Zn-AI15.
Zn-AI15 alloy melting point is 440 degrees intake, zinc-aluminum alloy coating density of about 5.0g/cm3.Zn-AI15 is in many respects superior to pure zinc or pure two-phase structure of the coating, The alloy coating in many environments with good corrosion resistance, Magnesia the steel substrate can provide effective protection. China has also been present in the commercialization of Zn-AI15 alloy thermal spray wire supply.
Zn-AI15 better mechanical properties of the coating alloy, its strength and hardness are superior to pure zinc coating and aluminum coating; between the electrochemical properties of zinc and aluminum coating between the two both some advantages. Corrosion in the steel structure of the application of aluminum and zinc or similar. Therefore, Zn-AI alloy coating is superior overall performance and Lv coating of zinc coating is a highly efficient room temperature electrochemical cathodic protection corrosion resistant coatings. Source:http://www.mhcocm.com
