L. Tomcsanyi et al., INVESTIGATION ON PASSIVATING FILM FORMATION ON ALUMINUM AND STEEL BY SPECIAL CV AND MICROCALORIMETRIC TECHNIQUES, Hungarian journal of industrial chemistry, 23(2), 1995, pp. 149-152
Passivating films formed on steel working electrodes were characterise
d by the values and ratio of the rate constants (k(ox)(0) and k(red)(0
)) of the charge transfer of the Fe(CN)(6)(3-)/Fe(CN)(6)(4-) redox cou
ple. k(0) values were determined by a special CV technique in the solu
tions containing both the oxidised and reduced forms of the redox coup
le. These values were influenced by the chemical composition of steel
and the chemical conditions of the solutions where the passive layers
formed. The small reaction enthalpies of the formation of the passivat
ing film on aluminum and steel were determined with a reaction microca
lorimeter. These reactions are exothermic for both metals. In the case
of aluminum the number of oxide monolayers was calculated on the base
of a model including the factors that control the passivation process
.