Effect of some Benzimidazolone compounds on C38 steel corrosion in hydrochloric acid solution

The inhibitive action of some benzimidazolone derivatives,namely 1,3-dihydro-2h-benzimidazol-2-one (bi1) and 1-(prop-2-en-1-yl)-1,3-dihydro-2h-benzimidazol-2-one (bi2) against the corrosion of c38 steel in molar hydrochloric acid solution has been investigated using weight loss measurements,tafel polarization and electrochemical impedance spectroscopy (eis) techniques. results obtained reveal that these derivatives perform excellently as corrosion inhibitors for mild steel in hcl 1m solution,its inhibiting efficiency reaches 92 % for bi1 and 95% for bi2 at 10-3 m. polarization measurements showed that bi1 is considered as an inhibitor of predominant anodic effect,but bi2 act essentially as a mixed type inhibitor with anodic predominance at 10-3 m. the temperature effect on the corrosion behavior of mild steel in 1 m hcl with and without bi1 and bi2 at different concentrations was studied in the temperature range from 303 to 333 k. e% remains the same even at high temperature for bi1 and bi2 at 10-3m . the adsorption free energy and activation parameters for the mild steel dissolution reaction were determined. both products are adsorbed on the mild steel surface according to a langmuir isotherm adsorption model. surface morphologies of sample were presented through scanning electron microscope (sem).