Classification of Marine Sacrificial Anodes
Marine sacrificial anode is a kind of protective measure for hull corrosion, which mainly protects the metal structure of hull from corrosion by electrochemical principle. There are three main categories: zinc anodes, magnesium anodes and aluminum anodes. These anodes have their own characteristics and uses according to their different materials and applicable environments.
Overview
1. Zinc Anode (Zinc Anodes)
Main features: good electrochemical performance in seawater, stable potential, long service life.
Advantages: more stable potential, suitable for seawater environment. It is not easy to form passivation film in the process of use, and the protection effect is long-lasting.
Disadvantages: less effective in freshwater environment.
Application: Widely used in marine environment, such as hull, side, bottom, propeller, marine cooling water system.
2. Magnesium Anode (Magnesium Anodes)
Main features: High electrochemical activity, suitable for high resistivity environment, such as fresh water and soil.
Advantages: Significant protection in fresh water and low resistivity environments. The potential is more negative, providing stronger electrochemical protection.
Disadvantages: faster depletion in seawater with high salt concentration. Higher price and large cost of use.
Application: Mainly used for hull anti-corrosion in fresh water environment, such as ships in lakes and rivers, and cooling water system in fresh water environment.
3. Aluminium Anode (Aluminum Anodes)
Main features: suitable for seawater and freshwater environment, high protection efficiency per unit weight.
Advantages: excellent electrochemical performance, applicable to a variety of environments. High protection capacity per unit weight, long service life. Lighter than zinc anode, easy to install.
Disadvantages: Potential is not as stable as zinc anode, using environment needs strict control.
Applications: commonly used on ship hulls, ship bottoms, marine cooling water systems, marine platforms, offshore structures, etc.
Choosing the suitable type of sacrificial anode requires comprehensive consideration of factors such as the use environment, protection object and economy. In general, zinc anode is suitable for marine environment, magnesium anode is suitable for freshwater environment, while aluminium anode has wide adaptability and can be used in a variety of environments.
