Definition
A list of metals and alloys arranged in order of their electrical potential when placed in a conductive solution such as seawater or moist salt air. Metals near the top of the list (the anodic or 'less noble' end) corrode preferentially when in electrical contact with metals farther down the list (the cathodic or 'more noble' end). The further apart two metals are on the list, the faster the more anodic metal will corrode when they are joined and exposed to moisture.
Plain English
A ranked list that tells you which metals will eat away at each other when they touch and get wet. The bigger the gap between two metals on the list, the faster the higher one will corrode.
Context Anchor
Seen in aircraft maintenance discussions about corrosion, especially where different metals are fastened together.
Derivation
From Luigi Galvani, an 18th-century Italian scientist who discovered that electrical current flows between two different metals in a moist environment. The 'series' is simply the ranked order of metals based on this effect.
Why Pilots Care
Aircraft contain many different metals joined together; using incompatible metals from opposite ends of the series without protection causes hidden corrosion that can weaken structures over time.
Grounding Statement
If aluminum and steel are joined and salty moisture gets between them, the galvanic series helps predict which metal is more likely to corrode.
Intuition Check
Do not read this as a list of strongest or best metals. It is a list about corrosion behavior when different metals are connected in a conductive liquid.
Example Sentence 1
The mechanic checked the galvanic series before installing the steel fitting against the magnesium housing to make sure the two metals wouldn't cause rapid corrosion.
Example Sentence 2
Zinc sacrificial anodes were chosen because the galvanic series showed they would protect the nearby steel landing gear components.