The values of cathodic Tafel slope
[beta]c and anodic Tafel slope
[beta]a were found to change with increasing inhibitor concentration, which indicated that the inhibitors control both anodic and cathodic reactions .
The different corrosion parameters are anodic Tafel slope
(ba), cathodic Tafel slope
Current-potential data, Tafel slope
b, diffusion coefficient, D and the charge-transfer rate constant, [k.
corr] value with the increase in the concentration of the inhibitor indicating that N-Benzylimidazole acted as an anodic inhibitor (Riggs, 1973) for MS in 1 N HCl which was supported by the gradual and significant decrease of anodic Tafel slope
2]), obtained graphically by intersecting point of the catholic Tafel and the anodic Tafel slope
c] are the Tafel slopes
or the Tafel constants, expressed in V/decade (V/dec), and [R.
5, the anodic and cathodic Tafel slopes
remain almost unchanged, indicating that the adsorptive nature of inhibitors molecules is not due to the interference on the reactions of metal dissolution and reduction of protons.
Where, B is a constant from anodic and cathodic Tafel slopes
(26 mV for actively corroding steel rod).
And the electrochemical corrosion kinetic parameters, such as corrosion potential (Ecorr), cathodic and anodic Tafel slopes
(ba, bc) and corrosion current density Icorr obtained by extrapolation of the Tafel lines are shown in Table 2.
The corrosion current density (icon-) for the particular specimens was determined by extrapolating the anodic and cathodic Tafel slopes
3 and the slight variation of the constant cathodic Tafel slopes
, bc, for the two studied inhibitors suggested that the cathodic process, the hydrogen evolution reaction, was activation controlled and the addition of heterocyclic amine derivatives did not modify the mechanism of this process [22,23].
a]) Tafel slopes
, the estimated corrosion current densities ([i.