Electrochemical Potentiodynamic Reactivation: Development and Applications of the EPR Test

The EPR test, designed to examine of the susceptibility to nonuniform, primarily intergranular corrosion, ranks among the more successful testing technique developments relating to stainless steels and alloys. One of its numerous advantages is that it lends itself to non-destructive, on-site examination. EPR enjoyed wide expansion over the years since first conceived by Čihal in 1969. Recent EPR measurements tend to focus on (1) double and/or single loop EPR as a modern technique used to establish the resistance of stainless steels and alloys to intergranular corrosion; (2) detecting integranular corrosion (IGC) and intergranular stress corrosion cracking (IGSCC) susceptibility in alloy steels and nickel alloys for nuclear engineering applications; and (3) studies of grain boundary precipitation and other minute local changes to alloy composition and structure.