Impedance of Fe80B20 Glassy Alloy in Sulphuric Acid

Experimental investigations of corrosion behavior of glassy metal Fesolfco in 1.0 mol dm"3 H2SO4 are described. Results are presented on voltametric and impedance measurements in three distinct anodic potential ranges. Two relaxation processes have been observed and identified: i) a kinetically controlled interfacial charge transfer mediated by adsorption of some intermediate species in the active dissolution range; ii) the same process, but with a blocking effect due to adsorption of the passivating species in the passivation or transition range; and iii) ion migration in a high electric field within the passive layer with adsorption of surface states in the passive range. Using a general impedance of the resistance, the measured impedances have been characterized in terms of parameters of compatible equivalent circuits