Photoelectrochemical study of pitting on iron in borate buffer solution containing inhibitor

The photoelectrochemical behavior and the susceptibility of iron to pitting in borate buffer containing chloride ions (Cl-) were investigated in the presence and absence of inhibitor PC-604(dagger), which is a mixture of polyhydric alcohol phosphoric ester and polyphosphoric ester of various molecular weights. Measurements of the band gap (E-g) of the passive film on iron showed inhibitor concentration and passivation time did not interfere with E-g. Photocurrent and photocurrent transients increased with increasing Inhibitor quantities and passivation times at constant potential. The decay time-constant of the photocurrent transient was investigated as a specific parameter of the film Data showed this parameter was related to pitting susceptibility of the passive film on iron.