Understanding Electrogalvanic Corrosion: Causes, Prevention, and Solutions

Electrogalvanic corrosion is a type of corrosion that occurs when two different metals are in contact with each other in the presence of an electrolyte, and one metal corrodes more quickly than the other. This can happen due to differences in the potentials of the two metals, which can cause one metal to act as an anode (a positively charged electrode) and the other metal to act as a cathode (a negatively charged electrode).

For example, if you have a steel bolt connected to a copper nut, and the assembly is exposed to saltwater or another electrolyte, the copper will tend to corrode more quickly than the steel due to its lower potential. This can cause the copper to act as an anode, while the steel acts as a cathode. As a result, the copper will lose electrons (corrode) and the steel will gain electrons, which can lead to pitting and other forms of corrosion on both metals.

Electrogalvanic corrosion can be a significant concern in marine environments, where there are many different metals that can be in contact with each other and with electrolytes. It is also a concern in other applications where dissimilar metals are used together, such as in piping systems or in the construction of buildings.

To prevent electrogalvanic corrosion, it is important to use materials that are compatible with each other, and to avoid exposing the assembly to electrolytes. If this is not possible, then coatings or other protective measures may be necessary to prevent corrosion. Additionally, regular inspection and maintenance can help to identify any signs of corrosion early on, before it becomes more severe.