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Cathodic Protection

3E-SERVICES is an expert agency in large scale adoption of the Cathodic protection system so as to ensure protection to base metals and structures in order to reduce the rate of corrosion and prolong the serviceable life of the structure. 3E-SERVICES has done extensive retrofitting works to protect large steel/ iron structures/ reinforcements by using this process of Cathodic Protection.

Why do we need Cathodic Protection?

  • The common term “rusting” is used to describe the start of corrosion. In electrochemical terms, the electrochemical reaction (commonly referred to as corrosion or “rusting”) starts the moment iron ions emerge from the Base metal.
  • To reduce the rate of Corrosion of a Metal, “Cathodic Protection” is an effective and time tested method adopted by 3E-SERVICES.
  • Corrosion of metals is the most feared and undesirable occurrence in any Building and Infrastructure project including Industrial structures. Corrosion leads to huge damage to structures, drastically reducing the life of the structure and has a tremendous impact on cost and profitability of process plants and Industries. More importantly, if not checked in time, corrosion leads to huge safety hazards and is a threat to people living and working in such structures.
  • Corrosion of metals is an Electro-chemical process. Wherever the corrosive metal like Iron is in an environment of Soil or Water, corrosion is inevitable.
  • Hence, in order to protect the metal from corrosion, either they should be well protected or the rate of corrosion has to be drastically reduced so as to extend the life of the metal.
  • At times, especially near corrosive environments like sea-proximity areas, polluted environments etc., the physical protection such as coatings/ paints etc., do not hold for a long time thereby allowing ingress of water or exposing base metal to soil. This leads to the onset of Corrosion. Hence it is prudent to adopt a dual approach of not only protecting the metal through surface coatings but also, in case of onset of corrosion, provide a second effective “barrier” called as “Cathodic protection” (CPHow Cathodic Protection Works?

How Cathodic Protection Works?

  • The Metal surface (Base metal) which has to be protected, is connected to a “sacrificial metal”, the base metal is made the Cathode while the “Sacrificial Metal” is made the anode.
  • The Sacrificial metal has higher reactivity than the Base Metal. Hence it is more sensitive to the Electrochemical Reaction and immediately starts reacting the moment it encounters formation of any iron ions by supplying electrons.
  • For an Electrochemical reaction to happen, a medium of Electrolytes is vital. Water, Concrete and soil are good electrolytes.
  • Therefore, whenever corrodible metals such as Iron come in contact with either soil or water, it triggers a reaction called Electrochemical reaction.
  • The Electrochemical reaction leads to formation of ions from the Base metal (Iron is the base metal considered as an example, to describe the case).
  • As the reaction continues, more Iron Ions are formed, weakening the base metal (Iron) ; this process is commonly called as “Rusting” or “Rust formation”. Rusting is physically seen as formation of Reddish-brown powder deposits on the metal surface.
  • Therefore, in order to stop “rusting” or corrosion of the base metal, the rate of formation of Iron Ions has to either be stopped or decelerated. Deceleration can be done by insertion of a “Sacrificial Metal” which has a higher rate of reactivity compared to the base metal.
  • Hence, if a “Sacrificial metal” is attached to the Base metal, then the Base metal becomes the Cathode and Sacrificial Metal becomes the Anode. This results in the sacrificial metal supplying electrons which attracts the Ions produced due to electrochemical reaction that is triggered by presence of electrolytes (such as water, soil etc). This prevents the ions from attacking the base metal (Iron in this case) as these ions are attracted by the electrons supplied by the sacrificial metal.
  • Hence, the Sacrificial metal “sacrifices” itself and protects the base metal by decelerating the rate of corrosion substantially..
  • The commonly used sacrificial metal is the Magnesium rod, TITANIUM mesh etc are referred to as the “Sacrificial electrode”. These are physically connected to the Base metal so as to complete the circuit to ensure proper electrochemical reaction.