Electrogalvanizing and hot-dip galvanizing are two common zinc coating methods, which are mainly used to improve the corrosion resistance of steel and other metal surfaces. 

Although their purpose is similar, there are some differences in the process, effect and scope of application of the two. The following are the main differences between electric 

galvanizing and hot dip galvanizing and their respective scope of application:

1. Electrogalvanizing

Technological principle

Electrogalvanizing is a process by which zinc metal is deposited on the surface of steel by electrolysis. Specifically, steel is used as the cathode and zinc as the anode, and an electric 

current is used to deposit zinc from the electrolyte to the metal surface, forming a thin zinc layer.

Peculiarity

Zinc layer thickness: The zinc layer of electrogalvanizing is thinner, usually between 5-25μm.

Coating uniformity: Due to electrolytic deposition, the coating is more uniform, suitable for products with higher surface requirements.

Appearance: electric galvanized surface smooth, bright, with good decorative.

Corrosion resistance: The corrosion resistance of electric galvanizing is not as good as that of hot dip galvanizing, because the coating is thinner and vulnerable to physical damage and 

exposure of the steel surface.

Advantage

Uniform and bright coating, beautiful surface.

Suitable for applications requiring higher surface quality and thinner coating.

Can achieve more complex shape galvanizing.

Shortcoming

Zinc layer is thin, corrosion resistance is weak, easy to be damaged in harsh environments.

It should only be used where it is not exposed to extreme environments.

Scope of application

Precision parts: such as auto parts, home appliance shell, hardware, etc.

Products with high surface requirements and good visual effects.

Suitable for applications not exposed to extreme weather conditions.

2. Hot-dip Galvanizing

Technological principle

Hot dip galvanizing is to immerse steel or other metals in a molten zinc bath, and react zinc with the surface of steel through high temperature to form a metal zinc alloy layer. The steel 

is immersed in zinc liquid at about 450°C at high temperatures, and an alloyed zinc layer is formed on the surface.

Peculiarity

Zinc layer thickness: The zinc layer of hot dip galvanizing is thicker, generally 50-200μm, or even thicker, with stronger corrosion resistance.

Coating adhesion: The zinc layer of hot dip galvanizing forms an alloy layer between metals and the base metal, which has strong adhesion and is not easy to fall off.

Rough surface: Due to the faster cooling rate of zinc in the process of hot galvanizing, the surface may be rough, and the surface color is gray or silver gray.

Advantage

The thick zinc layer has excellent corrosion resistance and can provide long-term protection.

It is suitable for products exposed to harsh environments, especially where corrosion resistance is required.

Hot dip galvanizing layer has strong adhesion, even when hit by external force, the zinc layer is not easy to fall off.

Shortcoming

The surface is relatively rough, and the appearance is not as beautiful as electric galvanizing.

The thicker coating is not suitable for products requiring higher precision and smooth surface finishes.

Scope of application

Building structure: such as steel structures, Bridges, fences, pipelines and other structural parts that need to be exposed to the outdoors for a long time.

Transportation facilities: such as power tower, communication tower, railway track facilities, etc.

Agricultural facilities: such as greenhouse, agricultural equipment, etc.

Other occasions with high corrosion resistance requirements: such as water treatment equipment, Marine engineering, chemical equipment, etc.

3. Summary of major differences

Sum up

Electrogalvanizing is suitable for those products with high surface quality requirements and mild environmental conditions, typical applications such as precision parts, home appliance

 housings and some hardware that is not often exposed to harsh environments.

Hot dip galvanizing is suitable for occasions with high corrosion resistance requirements, especially those exposed to outdoor, Marine or other harsh environment products, such as

 building structures, transportation facilities, etc.

The choice of the two usually depends on the needs of the actual application, including factors such as corrosion resistance, cost, appearance requirements and use environment.