The principle of this method is to force the metal to behave like a cathode by connecting it to a powerful anode metal plate.
These are of two kinds: (a) Sacrificial anodic protection: (b) Impressed current cathodic protection
(a) Sacrificial anodic protection
• In this method, the metallic structure to be protected is connected through a metallic wire to a more anodic metal so that all the corrosion will take place only on the anodic metal.
• The artificially made anode thus gets gradually corroded protecting the original metallic structure.
• This process k otherwise known as sacrificial anodic protection.
• Metals commonly used a sacrificial anodes re zinc, magnesium, aluminum and their alloys.