Zinc plating: galvanizing or zinc electroplating

As its name suggests, zinc plating, or galvanizing, is a process in which a zinc coating is applied to a metal surface (usually steel but others as well).

What is the purpose of galvanizing?

Galvanizing is used to protect metals from galvanic corrosion by hindering the formation of electrolytes with anodic action at the edges.

In fact, since zinc is less electronegative (i.e. less noble) than steel, it acts as a sacrificial anode in the event of electrolytic corrosion. Zinc plating guarantees an excellent quality coating and represents a valid alternative to other electroplating treatments such as chrome plating or nickel plating.

What are the most commonly used zinc plating techniques?

In practice, zinc plating can be applied using different techniques, but here we describe the most common.

• Electrogalvanizing (also known as zinc electroplating)

This process occurs through immersion in an electrolyte solution containing zinc salts. It is preferred for carefully hardened steel parts and precision parts.

• Cold galvanizing

When it comes to cold galvanizing, it is perhaps improper to talk about galvanizing in the strict sense, since from the technical point of view, this more properly involves a resin-based synthetic paint rich in zinc. This is a valid alternative in difficult-to-treat environments.

• Spin galvanizing and rack galvanizing

Based on the metal, spin galvanizing is suitable for small parts and rack galvanizing for larger or particularly delicate products.

How long does the protective effect of galvanizing last?

Galvanizing is a useful process for protecting steel from its enemy number one: rust. Corrosion gradually destroys metals, especially when exposed to unique environments. The environment surrounding the product certainly also impacts the duration of the galvanization.

Pre-treatment of the metal is important and paint is often applied after galvanizing for further protection, in order to increase the strength of the treatment.

Although galvanizing was discovered more than a century ago, it is still an effective technique that provides excellent results against metal corrosion.