What is Electrogalvanization?

Electrogalvanization is a process used in metalworking as corrosion prevention. A zinc electroplating, process or galvanization process, adheres a layer of zinc to the surface of steel to inhibit rust and corrosion. Zinc is not subject to normal corrosion, so this metal plating protects the steel that lies underneath the plating.

This electroplating process uses a sacrificial zinc anode suspended in a solution of zinc and saline. An electrical current is introduced to this setup with the zinc anode being attached to the positive side of the power source while the steel to be galvanized is attached to the negative side of the power source. By attaching the power supply in this manner, the positively charged zinc ions given off by the anode are attracted to the negatively charged steel.

This process is used as a method of corrosion prevention for a variety of manufactured products. Galvanized nails, screws, wiring and pipes are common examples of the products that are treated using electrogalvanization. In addition, the automotive industry has made extensive use of the electrogalvanization process to protect the body panels, frames and other components of automobiles.

The use of electrogalvanization as an anti-corrosion layer is common for products that are used in an environment where they would be exposed to weather conditions or corrosive elements. Products made with electrogalvanized steel remain useful long after the same product made from regular steel would have been reduced to rust, because of the rust prevention qualities of electrogalvanization. From wire fences and electrogalvanized steel gates to highway signs and household appliances, electrogalvanization is used almost anywhere a long-lasting metal product is desirable.

By adding chemical components to the zinc and saline solution used in the electroplating process, additional benefits can be gained. Automotive manufacturers commonly use a technique called prephosphating to improve the surface adhesion of paint to the electrogalvanized parts. By adding phosphate salts or other chemicals to electrogalvanization solution, various benefits — such as the improved adhesion of paint, lubrication or coloring — can become a long-lasting effect because the chemicals are embedded in the electroplated zinc layer.

Electrogalvanization is not the same process as zinc plating. The electrogalvanizing process requires the use of electricity to create a layer of zinc on the steel conductor. This process is more permanent than zinc plating through processes such as hot dipping, because the zinc actually adheres to the steel at a molecular level rather than being merely a coating added to the steel. This is an important distinction, but the misidentification of zinc plating as electrogalvanization is quite common.