ELECTROCHEMICAL IMPEDANCE :THE DOUBLE LAYER CAPACITANCE AS A PROBE OF THE ORIGIN OF THE TIME-CONSTANTS

摘要

A new experimental approach is proposed for investigating the origin of the faradaic time-constants of solid electrodes. The double layer capacitance measured at a frequency high enough for not altering the interfacial configuration displays a low-frequency response tightly correlated to the faradaic impedance. The original experimental arrangement and results dealing with anodic dissolution and passivation of iron and nickel give preliminary, but clear trends on the relation between double layer properties and the presence of interfacial species, either passivating or intermediate state of metal dissolution.