What should be done to make bonding or grounding connections between dissimilar metals?

Using a suitable washer to ensure that any corrosion occurs on the washer is the correct approach for making bonding or grounding connections between dissimilar metals. When two different metals are in contact, there is a risk of galvanic corrosion, which occurs when an electrical potential difference causes a reaction that corrodes the less noble metal.

By placing a washer made of an appropriate material between the two dissimilar metals, the washer acts as a sacrificial barrier. This means that the washer will corrode instead of the underlying metals, thereby preserving the integrity of the more critical components of the connection. Additionally, selecting a washer that has a similar hardness and chemical compatibility can help maintain strong electrical conductivity and mechanical stability.

This method is widely used in aircraft and other applications where dissimilar metals are frequently encountered, as it provides a practical solution to mitigate corrosion risk while maintaining proper electrical bonding.