Science behind the magic
Cathodic Protection reduces the corrosion
of metal surfaces by making the steel surface the cathode of an
electro-chemical cell by using either a galvanic sacrificial anode,
usually an electrochemically active alloy such as aluminium, zinc or
magnesium, or by using an impressed current system.
The sacrifical
system is usually more expensive due to the cost of the galvanic anodes
used. However, since galvanic anode systems require no external source
of power and are relatively easy to install and maintain, they are
becoming more attractive, according to MCPS Ltd.
The fact that
aluminium prices are falling is making the solution even more
attractive. Compared to zinc anodes, aluminium alloy anodes have a
higher electrochemical efficiency which enables them to operate at
different temperature co-efficients. The anodes are less dense than
zinc making them lighter and easier for handling when fitting and
systems based on this technology can also be designed to protect the
uncoated steel on older installations.
