In any corrosion cell, the site where metal gives up electrons and goes into solution, so it is the area that corrodes, and current leaves it into the electrolyte. In cathodic protection the word also names the hardware deliberately placed to play that role: sacrificial anodes of magnesium, zinc or aluminum that are consumed, or impressed-current anodes of mixed metal oxide, graphite or high-silicon cast iron that discharge rectifier current.
Readings drop off past mile post 12, the anodes on that stretch are probably spent.
Also heard as
- anodic site
Do not mix it up with
- Cathode: The anode is where corrosion and current discharge happen; the cathode is the protected side where current is collected.
Related terms
Cathode
Electrode where reduction happens and current is collected, so the metal there does not corrode.
Sacrificial anode
Block of a more active metal such as magnesium, zinc or aluminum that corrodes to protect connected steel.
Groundbed
Group of impressed-current anodes buried in backfill that discharges rectifier current into the earth.
Electrolyte
Conductive medium such as soil, seawater or concrete pore water that carries ionic current between anode and cathode.