Sacrificial anode
A sacrificial anode is a less noble metal that supplies protective current and prevents corrosion by corroding itself.
Physicochemical Mechanism of Action
The sacrificial anode is a less noble metal placed in contact with a more noble material. It supplies the protective current for cathodic corrosion protection through its anode properties. The corrosive reaction on the sacrificial anode releases electrons that flow to the cathodic side (the noble material to be protected) and are neutralized there.
Metallurgical Relevance & Welding Risks
Proper selection and placement of the sacrificial anode are crucial for corrosion protection. Incorrect choice can lead to accelerated corrosion or make the protection ineffective. It is important that the sacrificial anode is made of a less noble metal than the material it protects.
Workshop Practice & Action Guidelines
When installing a sacrificial anode, the following steps must be observed:
• Choose a less noble metal that is more anodic than the material to be protected.
• Ensure the sacrificial anode is well connected to the noble material and maintains contact.
• Regularly monitor the condition of the sacrificial anode and replace it at the first signs of corrosion.