Abstract
The corrosion behaviour of mild steel in 1M HCl containing organic compounds such as: 2,2'-bipyridine (inh1), 1, 10-phenanthroline (inh2), 4,4'-6,6'-tetramethyl-2,2'-bipyridine (inh3) and 2,9-chloromethyl-1,10-phenanthroline (inh4), was studied by weight loss and electrochemical polarization methods. Polarization data indicate that all tested compounds are mixed-type inhibitors affecting both cathodic and anodic processes. The inhibition efficiency of these additives increases in the order: inh3 < inh1 < inh2 < inh4. The adsorption of 2,9-chloromethyl-1,10-phenanthroline on the mild steel surface in 1M HCl medium follows a Langmuir adsorption isotherm. The effect of temperature indicates that the inhibition efficiency of inh4 is temperature independent in the range 25 to 90 degrees C. The apparent activation energies in the absence and in the presence of inh4 were determined.