impressedcurrenttilkobling

Impressed current cathodic protection (ICCP) is a corrosion control method that uses an external power source to supply a controlled direct current to a metal structure. By driving the structure’s electrochemical potential to a more negative value relative to a reference electrode, anodic dissolution is suppressed and the corrosion rate is reduced. ICCP is contrasted with galvanic (sacrificial) protection, which relies on more noble anodes without an external power source.

A typical ICCP system includes a rectifier or power source, electrical conductors, and anodes placed in contact with the environment surrounding the protected structure. Common anode materials are mixed metal oxide-coated titanium, graphite, or other corrosion-resistant composites. A remote reference electrode and monitoring equipment are used to measure potentials and regulate current, ensuring the protected surface remains within a designated protective range.

Operation involves applying current from the power source to the anodes, which draw electrons through the surrounding medium (soil, water, or concrete) to the protected structure, making it the cathode. The resulting potential shift reduces metal dissolution at the surface. Protective effectiveness is verified by regular potential measurements and current density checks, with adjustments made via the rectifier settings. ICCP systems are designed for long-term protection and are frequently used where coating integrity is imperfect or where large structures require substantial, adjustable current.

Applications include pipelines, offshore platforms, ships hulls, storage tanks, and reinforced concrete elements. Design considerations cover soil or water resistivity, coating condition, required current density, anode type and layout, and monitoring strategies. Advantages include controllable, scalable protection for large structures; disadvantages involve energy costs, ongoing maintenance, and potential interference with nearby electrical systems.