Anodic Index: how to measure? 1

[Tunalover]

It's easy to find the AI values of various metals but how is the AI measured? Is there some test that standardizes how it is done and DEFINES the AI from a theoretical standpoint? After all, all those published AIs had to some from somewhere!


Tunalover

 

[mshimko]

Generally one measures the free corroding potential of a metal relative to a standard electrode (several are common). The materials are then listed by order of their free corroding potential.

Before this post, I hadn't heard the term "anodic index". Its not listed in McGraw-Hill's Dictionary of Scientific and Technical Terms, ASTM G 15-93, or ASM Handbook Vol 13 Corrosion.

Looking at a few "hits" on the internet, it appears an "anodic index" is simply a galvanic series with the numeric values adjusted not to a standard electrode, but to gold, with gold = 0.0 volts.