The state of the surface of a metal or alloy susceptible to corrosion where its electrochemical behaviour becomes that of less reactive metal and its corrosion rate is reduced.

NOTE: This is generally the result of protective film formation.


pH value
A logarithmic index for the concentration of hydrogen ions in an electrolyte.

NOTE: See A.1.

Containing an excess of hydrogen ions over hydroxyl ions.

Containing an excess of hydroxyl ions over hydrogen ions.

Containing equal concentrations of hydrogen ions and hydroxyl ions

A non-uniform corrosion of a metal whereby a number of cavities, not in the form of cracks, are formed in the surface.

Change in the potential of an electrode as the result flow.

polarisation cell
A device inserted in the earth of a structure that drains only a small current from the source used to provide cathodic protection for the structure, but provides a low resistance path to currents from high d.c. voltages and all a.c. voltages carried by the structure.

protection current
The current made to flow into a metallic structure from its electrolytic environment in order to effect cathodic protection of the structure.

protection potential
The more negative level to which the potential of a metallic structure, with respect to a specified reference electrode in an electrolytic environment, has to be depressed in order to effect cathodic protection of the structure.

protective coating
A dielectric material adhering to or bonded to a structure to separate it from its environment in order to prevent corrosion.

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The Aquamatic®

Impressed Current Cathodic Protection System

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Anfomatic System (MGPS)

Electrolytic Antifouling System