Active-Passive Behavior and Susceptible Zone of Potentials

9 Active-Passive Behavior and Susceptible Zone of Potentials 

An example of the behavior is shown by stainless steel in 1.0 M sulfuric acid solution. Transgranular SCC can occur in two ranges of potentials. Intergranular SCC can occur in a wider potential range. The potential zones 1 and 2 correspond to the active-passive and passive-active state transitions. The crack tip corresponds to the crack tip and the passive state, or film formation corresponds to zone 2. Zone 2 is frequently above the pitting potential, indicating the possible pit initiation and propagation. 

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