Glossary

Deutsch: Kathodischer Korrosionsschutz / Español: Protección Catódica / Português: Proteção Catódica / Français: Protection Cathodique / Italiano: Protezione Catodica

Cathodic protection in the industrial context is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. This method is widely used in various industries to protect metal structures from corrosion in aggressive environments, such as pipelines, underground storage tanks, ship hulls, offshore oil platforms, and reinforced concrete structures.

Description

Cathodic protection works by applying a direct current from an external source (sacrificial anodes or impressed current systems) to the metal in need of protection. This process reduces the metal surface's potential, preventing the electrochemical reactions that lead to corrosion. There are two main types of cathodic protection:

• Sacrificial Anode Cathodic Protection (SACP): Uses more reactive metal anodes (zinc, magnesium, or aluminum) that corrode instead of the protected metal.
• Impressed Current Cathodic Protection (ICCP): Involves applying a direct current to the protected metal from an external power source, using inert anodes like titanium coated with mixed metal oxides.

Application Areas

• Pipelines and Distribution Systems: Protecting underground and underwater pipelines from corrosion to ensure the safe transport of oil, gas, and water.
• Marine Structures: Used for ships, harbor structures, and offshore platforms to prevent seawater corrosion.
• Storage Tanks: Protection of both underground and above-ground storage tanks containing water, petroleum products, or chemicals.
• Steel-Reinforced Concrete: In bridges, parking garages, and marine structures, where steel reinforcement could corrode due to chloride exposure or carbonation.

Well-Known Examples

• The use of magnesium anodes attached to underground pipelines or the hulls of ships to protect them from rusting.
• The installation of ICCP systems in large infrastructure projects, like bridges or water treatment plants, to ensure the longevity of the steel reinforcement.

Treatment and Risks

While cathodic protection is highly effective in mitigating corrosion, it requires careful design, regular monitoring, and maintenance to ensure long-term effectiveness. Inadequate application or system failure can lead to accelerated corrosion. Environmental considerations, such as the impact of sacrificial anode materials or the stray current from ICCP systems, also need to be managed.

Similar Terms or Synonyms

• Anti-corrosion protection
• Electrochemical protection

Summary

Cathodic protection is an essential corrosion control strategy in the industrial sector, safeguarding valuable metal assets from degradation. By converting the protected structure into the cathode of an electrochemical cell, it significantly extends the life of infrastructure and equipment in corrosive environments, ensuring operational integrity and safety.

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