Nickel Pourbaix Diagram
Corrosion Potentials:
The Pourbaix diagram indicates that below a pH of 9 nickel has the potential to form a corrosive ion. Since D.I. water typically has a pH value less then 6, thermodynamically nickel can corrode. Above a pH of 9 the most stable species for nickel is NiO.
Corrosion Rates:
The Tafel plots show that With the addition of a corrosion inhibitor, the corrosion rate of nickel can be reduced from 1.33 angstroms/minute to 0.076 Angstroms/minute.