What type of corrosion occurs when two different metals are in physical contact in a corrosive environment?

The type of corrosion that occurs when two different metals are in physical contact in a corrosive environment is known as galvanic corrosion. This phenomenon occurs because of the electrochemical potential difference between the two dissimilar metals. When they are connected electrically and exposed to an electrolyte (such as saltwater), one metal acts as an anode and the other as a cathode. The anode, which is the less noble metal, will corrode at an accelerated rate compared to how it would corrode alone, while the cathode, or the more noble metal, will be protected.

Galvanic corrosion is significant in marine applications because the presence of a conductive electrolyte (like seawater) can easily facilitate this type of corrosion when vessels are constructed using mixed metals, such as aluminum and stainless steel. Understanding this process is vital for marine corrosion prevention so that appropriate measures (like galvanic isolators or the use of sacrificial anodes) can be employed to mitigate the effects.

Pitting corrosion, uniform corrosion, and crevice corrosion, while important forms of corrosion in their own right, do not specifically relate to the contact of dissimilar metals in corrosive environments in the same way that galvanic corrosion does. Pitting typically refers to localized corrosion,