Sacrificial anode cathodic protection is a method to prevent metal corrosion by using the principle of galvanic cell. The specific method is to reduce the metal as a protective pole, and the metal to be protected connected to form a galvanic cell, the metal will be reduced as a negative oxidation reaction and sacrifice consumption, the metal to be protected as a positive pole, from being corroded. This consumes the metal at the expense of the anode (negative electrode of the galvanic cell) and protects the cathode (positive electrode of the galvanic cell). So it’s called sacrificial anode cathodic protection. Colloquially, it is the use of anode metal corrosion to protect cathode metal and slow down corrosion. For further understanding, the following concepts should be understood.
Electrochemical corrosion occurs when two metals with different potentials are exposed to water, because the two metals with different potentials form a microgalvanic cell. The corrosion rate of base metal with negative potential was accelerated while that of noble metal with positive potential was slowed down. For example, when copper and iron come into contact in water, iron is more reductive than copper and corrodes as an anode. Less reductive than iron, copper is the cathode and is not corroded. This corrosion phenomenon is called galvanic corrosion.
Sacrificial anode protection technology in many equipment structure, the building and the construction of the set, to prevent or slow the corrosion of steel and other metal materials cover a wide range of applications such as oil, petrochemical, natural gas pipeline and storage tank, ports, bridges, ships, submarine cable pipelines, water treatment plant, petrochemical plant, refinery, sluices, reservoirs and other equipments.Both construction and operation processes require consideration and sacrifice of anodes to protect equipment, pipes, gates, vessels, etc. Sacrificial anode protection is a systematic engineering, which requires detailed engineering calculation, selection of anode metal materials, and design and construction of collocation mode, so as to achieve the best sacrificial anode protection cathodic equipment, pipelines and other facilities to slow down corrosion and safely extend the service life.