What Is Galvanic Corrosion and How Do You Prevent It?


Galvanic corrosion, also known as bimetallic corrosion, is an electrochemical process in which one metal preferentially corrodes when in contact with another metal through an electrolyte.


THE PROCESS RESPONSIBLE FOR GALVANIC CORROSION

It is only when two dissimilar metals or alloys with distinct electrode potentials come into contact that galvanic corrosion may occur. The anode consists of the lower-quality metals, whereas the cathode is made up of the higher-quality metals. The anode is attacked more quickly due to the potential difference between the two electrodes, and it ultimately dissolves in the electrolyte, while deposits build up on the metal cathode.


To accelerate the corrosion of the anode metal while slowing its impact on the cathode metal, electrolytes promote ion migration from the anode to the cathode. It is necessary to have an electrolyte present so that the ions may continue to move and cause galvanic corrosion.


While it's not a desirable process, there are times when it comes in handy. Primary batteries typically have carbon-zinc cells, which are designed to promote the preferred corrosion of zinc, resulting in an electrical voltage. In the cathodic approach, the anode material corrodes to neutralize the cathode metal's corrosive impact, which is useful for preserving underground buildings.


HOW TO PREVENT GALVANIC CORROSION

  1. Breaking the electrical connection between the two metals by isolating them from one another.

  2. Introducing anti-corrosion agents into the environment.

  3. Choosing materials with comparable corrosion potentials.

  4. Separating the two materials by inserting a spacer of the appropriate size.

  5. Coatings are applied to both materials. The cathode's coating is crucial and must be in excellent condition; otherwise, galvanic corrosion might be exacerbated.

  6. Installing a sacrificial anode that is anodic to both metals.


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