ICCP versus galvanic cathodic protection

Cathodic protection can be achieved in two main ways: using galvanic anodes (GCP – Galvanic Cathodic Protection) or impressed current (ICCP – Impressed Current Cathodic Protection). Both techniques have the same objective: to polarise the protected metal to a sufficiently negative potential so that the corrosion rate is significantly reduced.

Galvanic system

In galvanic cathodic protection, sacrificial anodes are made from a metal that is electrochemically more active than the structure being protected, such as zinc, magnesium, or aluminium. The potential difference generates a protective current spontaneously, without the need for an external power source.

This type of system is relatively simple, robust, and low-maintenance. It is often used for smaller structures or installations with a limited current demand, and in situations where an external power supply is unavailable or undesirable.

Impressed current

With ICCP, the required protection current is supplied by an external power source, typically through a rectifier connected to the electrical grid. The current is injected into the electrolyte via one or more inert or dimensionally stable anodes and can be accurately adjusted to the required protection conditions.

ICCP offers a higher and controllable current capacity, making it particularly suitable for larger structures, installations with a higher current demand, or situations where the protection parameters need to be actively adjusted and monitored.

Which technique is most suitable?

The choice between ICCP and galvanic protection mainly depends on the required protection current. This, in turn, is influenced by several factors, including the size and geometry of the structure, coating condition, environment, electrical resistivity of the electrolyte, and required service life.

A galvanic system is not automatically better simply because it is more straightforward, just as ICCP is not automatically better because it is adjustable. A correct design always starts from the technical and electrochemical conditions of the specific installation.

Cathec assesses these parameters during the preliminary study using various techniques and, based on the results, determines which protection method is technically and economically the most suitable.