Galvanic series
An ordered list of metals and alloys by their measured potential in a given electrolyte, used to predict which of two coupled metals will corrode preferentially. ASTM G82 is explicit that a series is specific to its electrolyte and is a guide to ranking, not a prediction of rate.
A galvanic series answers one question: of these two metals, which one is the anode. It does not answer how fast, and a series measured in seawater does not transfer to a different electrolyte.
The factor a series omits entirely is area ratio. A small anode coupled to a large cathode concentrates the whole current on the smaller part, which is why coating the active metal and leaving one pinhole is worse than leaving it bare.
Sources and references
- StandardASTM G82-98(2014) — Standard Guide for Development and Use of a Galvanic Series for Predicting Galvanic Corrosion PerformanceASTM International · accessed August 29, 2026
Where this is covered in depth
- Galvanic corrosion in mixed-metal assembliesWhy the small part usually fails first, how the area ratio decides the severity, and why coating the wrong component makes the problem worse.
- Anti corrosion coating types: choosing by exposure zoneFive coating families, and the order that picks between them: corrosivity category first, durability class second, product last.