Electrodissolution Kinetics of Iron in Chloride Solutions Part I. Neutral Solutions

Anodie dissolution of iron in unbuffered neutral chloride solutions has been investigated by transient polarization techniques. A new method to cor-rect for the ohmic potential drop has been proposed. It has been observed that the anodic Tafel slopes were 40 mV/decade for fast polarization and 80 mV/ decade for slow or steady-state polarization. Steady-state anodic character-istics of iron have been studied by superimposing short cathodic potential and current pulses. At steady-state anodic polarization a Tafel relation was ob-tained between the cathodic potential (r and the cathodic current (ic) with a Tafel slope of about 120 mV/decade for both potentiostatic and galvano-static pulses. The difference in anodic Tafel slopes has been interpreted in terms of the formation of a hydroxochloro-iron complex, [Fe (OH) m (C1) n] 2-m-". The cathodic pulse polarization results indicate that m = 1. Numerous tudies of the anodic dissolution of iron in acidic chloride solutions have been carried out