Avionics Corrosion Control Practice Test

Using a washer made of anodic materials between dissimilar metals is a critical practice in corrosion control, particularly in the context of galvanic corrosion. Galvanic corrosion occurs when two different metals are in electrical contact in the presence of an electrolyte, leading to the more anodic (less noble) metal corroding faster than it normally would.

By introducing a washer made of an anodic material between these dissimilar metals, you can help to create a barrier that minimizes direct contact and potential electron flow between the different metals. The anodic washer will corrode preferentially, thereby protecting the more cathodic metal from corrosion. This strategy effectively sacrifices the washer to save the structural integrity of the other metals involved.

Choosing washers made from identical or similar materials, or connecting metals that are opposite in terms of their galvanic series position without the use of a protective barrier, does not effectively mitigate the risk of galvanic corrosion. In fact, it may exacerbate the problem, as there would be greater potential for direct corrosion between the dissimilar materials without a sacrificial element in place.