* Anodes used for Cathodic Protection are typically referred to as Sacrificial or Galvanic Anodes.
* Materials used for sacrificial anodes are metal alloys usually of aluminum, zinc, or magnesium.
* In order for an anode to function properly it needs to be within an electrolyte such as water, sea water, brackish water, soil, or mud.
* The anode "sacrifices" to the structure it protects by electrolytic action because the anode corrodes more easily than the cathode. (The structure being protected becomes the cathode)
Any time you have two different metals that are physically or electrically connected and immersed in seawater, they become a battery. Some amount of current flows between the two metals. The electrons that make up that current are supplied by one of the metals giving up bits of itself-in the form of metal ions-to the seawater. This is called galvanic corrosion and, left unchecked, it destroys underwater metals.
