Definition - What does Flade Potential mean?
The Flade potential refers to a metallurgical term used to describe the change in Gibbs free energy of a metal immediately before a final transition step from the passive to the active region.
The Flade potential is used to empirically examine the likelihood of passivation in a given metal, which is the process through which metals are safeguarded against corrosion. It aims to reduce the deterioration of metals caused by their reaction with the environment by applying an exterior secondary metal layer (a passivating film) to a substrate to protect it from corrosive reactions.
Corrosionpedia explains Flade Potential
In most cases, the passivating film is made up of oxides of metals. The formation and growth of passive films is vital for adequate protection.
The anodic polarization curve for a metal shows an active–passive transition and by extension, the Flade potential. Important characteristics to describe passive behavior are current density (ipass), the potential (Epass) and the passive current density (ipp). ipp is a measure of the protective quality of the film. ipass typically is orders of magnitude lower than corrosion current densities for active dissolution. Together, all parameters are indicative of the passivation ability of the alloy.