Cathodic protection

Definition

Cathodic protection is a technique used to prevent the corrosion of metal surfaces by making them the cathode of an electrochemical cell. This is achieved by connecting the metal to a more easily oxidized 'sacrificial' anode.

5 Must Know Facts For Your Next Test

1. Cathodic protection works by reducing the oxidation reaction on the protected metal surface.
2. Two common methods of cathodic protection are sacrificial anode and impressed current systems.
3. Sacrificial anodes are typically made from metals like zinc, magnesium, or aluminum.
4. Impressed current systems use an external power source to provide a constant protective current.
5. Cathodic protection is widely used in pipelines, ships, offshore platforms, and storage tanks.

Review Questions

• What is the primary purpose of cathodic protection?
• Which metals are commonly used as sacrificial anodes in cathodic protection?
• How does an impressed current system differ from using sacrificial anodes?

Related terms

Anode:

The electrode where oxidation occurs in an electrochemical cell. In cathodic protection, it is often sacrificed to protect another metal.

Corrosion:

The gradual destruction or deterioration of metals due to chemical reactions with their environment.

Electrochemical Cell:

A device that generates electrical energy from chemical reactions or facilitates chemical reactions through the introduction of electrical energy.