Zinc plating is a metalworking process that applies an outer layer of zinc to protect and strengthen metals against corrosion from external agents or wear over time. Zinc plating prevents micro electrolytic cells with anodic action from forming in the metal. Why zinc? Simply because it is less electronegative than steel and can therefore prevent corrosion by protecting the underlying metal.
Types of zinc plating
There are several types of zinc plating: the most common are hot-dip, cold and electrolytic. The differences relate to how the process is carried out and, of course, to the final result. In hot-dip galvanising, the steel is immersed in a bath of liquid zinc at 450°C. In cold galvanising, a coating based on synthetic resins loaded with zinc is used as a primer, exploiting its anti-oxidant properties; alternatively, the steel is immersed in a solution of zinc salts and electricity, through electrolysis, allows the zinc to form a layer on the sheet. Compared with hot-dip galvanising, this offers less protection because the zinc layer is thinner.
Electrolytic zinc plating, also called galvanic zinc plating, involves immersing a material in an electrolytic solution containing zinc salts. Compared with hot-dip or cold galvanising, it is ideal for protecting precision components.