What is Electro Galvanizing?
Electro galvanizing is a process in which a layer of zinc is bonded to steel in order to protect against corrosion. The process involves electroplating, running a current of electricity through a saline/zinc solution with a zinc anode and steel conductor. Zinc electroplating maintains a dominant position among other electroplating process options, based upon electroplated tonnage per annum. According to the International Zinc Association, more than 5 million tons are used yearly for both Hot Dip Galvanizing and Electroplating. Compared to hot dip galvanizing, electroplated zinc offers these significant advantages:
Lower thickness deposits to achieve comparable performance
Broader conversion coating availability for increased performance and colour options
Brighter, more aesthetically appealing, deposits
Electrogalvanized coatings are applied to sheet steels and wire; and therefore, are used in similar applicationsto continuous sheet galvanizing or wire galvanizing.The most common applications are in automobile andappliance bodies and fasteners. Furthermore, to extendthe service life, electrogalvanized coatings can be treatedto make them suitable for painting, and this is often recommended due to the extremely thin zinc coating.
Coating Characteristics
This electro-deposited zinc coating consists of pure zinc tightly adherent to the steel. The coating is highly ductile remaining intact even after severe deformation. Produced on strip and sheet materials, the coating weight ranges up to 0.2 oz/ft2 (60 g/m2), or thicknessesup to 0.36 mils (9.1 μm) per side, while on wire, coating weights may reach up to 3 oz/ft2 (915 g/m2). The coating of pure zinc is thinner than continuous sheet galvanizing, mechanically-bonded, and there are no alloy layers, but provides a smoother finish. Heat-treated and electro-coated wire can be cold drawn to about 95% reductionin area, depending on the chemical composition of the wire, heat treatment, and diameter.
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