Corrosion Inhibition of Stainless Steel in 0.5 M HCI by C_6H_5NH_2

摘要

In this study, different concentrations of C_6H_5NH_2 (Aniline) were employed for investigating its corrosion inhibition of stainless steel in 0.5 M HCI. Corrosion rate measurements at 28°C, 45°C and 60°C were obtained from a linear sweep voltametry instrument and analyzed for inhibition efficiency and apparent activation energy in the presence and absence of C_6H_5NH_2. Results showed that C_6H_5NH_2 generally exhibited excellent inhibition effects on stainless steel corrosion at the higher temperatures, i.e. the 45°C and 60°C, at which the self-protectiveness of the stainless steel metal appears to breakdown. In contrast, the stainless steel metal exhibited self protection in the presence and absence of C_6H_5NH_2 at the low temperature of 28°C, such that very low inhibition effects of aniline appears to be required at this temperature. Thus, while maximum inhibition efficiency (η) = 23.13% at 28°C by the 0.086 M C_6H_5NH_2, inhibition efficiency was as high as η = 96.00% by 0.043 M C_6H_5NH_2 at 40°C and η = 95.58% by the 0.107 M C_6H_5NH_2 at 60°C on stainless steel corrosion in the HCI test-medium. Apparent activation energy analyses showed that this thermodynamic quantity decreased in values from the uninhibited, E_a - 100.37 kJ/mol, to the excellently inhibiting 0.107 M C_6H_5NH_2 for which E_a = 6.30 kJ/mol. The implications, of these results, on the temperature dependency of C_6H_5NH_2 corrosion inhibition performance as well as on the dominance of chemisorption adsorption mechanism by this chemical inhibitor on the stainless steel metal were detailed in the study.