Weight: Aluminium is significantly lighter than zinc. Aluminium is only 40% as dense as zinc, making it easier to transport and install.

Capacity: Aluminium has more than three times the electrochemical capacity of zinc compared to the same mass of zinc, which means that the same protection can be achieved with fewer anodes.

Drive Voltage: Aluminium anodes have a higher drive voltage, which means that they provide a better current distribution compared to zinc.

Environmental friendliness: Aluminium anodes have better environmental friendliness than zinc anodes. Aluminium anode alloys do not contain cadmium, whereas zinc anodes contain cadmium, which is harmful to marine life.

Cost: Aluminium is cheaper per unit, and the same weight of aluminium anode can provide longer protection, so the cost of aluminium anodes is relatively lower.

Availability: Traditionally used in offshore oil projects, therefore zinc anodes are widely used.

Geometry: Zinc anodes can be produced in quite complex geometries compared to aluminium. This is particularly important for elongated structures, such as wire rope protection anode rings.

Appearance: Aluminum anodes tend to look slightly brighter than zinc anodes. 

Application: Zinc anodes can only be used effectively in salt water, while aluminum anodes can be used in saline and low-salt water.

No restrictions on use in containers: Zinc anodes are not subject to the same category restrictions as aluminium and are used in containers in potentially explosive atmospheres.

More uniform corrosion on the anode surface: Zinc anodes dissolve easily and are more uniform and complete, whereas typical aluminium anodes corrode unevenly, with visible "pits".

Comparison Perfomance of Aluminium and Zinc Anode