electrogalvanizing

Electrogalvanizing is a method of applying a zinc coating to steel or iron by electroplating. In this process, the workpiece to be coated serves as the cathode in an electrolytic cell, while zinc acts as the anode and dissolves into the electrolyte to furnish Zn2+ ions that deposit on the surface. The electrolyte typically consists of zinc salts in water, and may be cyanide-based or cyanide-free, with bath temperature and current density controlling coating thickness.

After proper cleaning and surface preparation, parts are immersed in the plating bath and connected to an external current source. By adjusting current density and immersion time, coatings typically range from about 5 to 25 micrometers, producing a bright, uniform finish that can be matte or bright depending on additives and post-treatment. Common post-treatments include chromate or passive coatings to improve corrosion resistance and appearance.

Compared with hot-dip galvanizing, electrogalvanized coatings are thinner and more uniform, especially on complex geometries, pipes, fasteners, and small or intricate parts. They offer excellent control, smoother surfaces, and reduced distortion but generally provide lower overall corrosion resistance in severe environments, so selection depends on service conditions. Edge coverage can also be a challenge, and some baths require strict control to avoid hydrogen inclusion.

Applications span automotive components, appliances, hardware, electrical enclosures, and decorative hardware where an even, controlled zinc coating is desired. Environmental and safety concerns have driven shifts toward cyanide-free electrolytes and careful waste management. The process is a common finishing option that complements hot-dip galvanizing for corrosion protection and coating versatility.