Corrosion Inhibition Property of a Novel Heterocyclic Compound in 0.5 mol/L H₂SO₄ Solution for Q235 Steel

A newly synthesized triazole,1-phenyl-2-(5′-(1′,2′,4′)triazol-1-ylmethyl-(1′,3′,4′)oxadizaol-2-ylsulfanyl)-ethanone (PTOE),as a corrosion inhibitor for mild steel in 0.5 mol/L H2SO4 was investigated using weight loss experiment,electrochemical test and quantum chemical calculations.The surface morphology after corrosion test was observed by scanning electron microscopy (SEM).It was found that the highest inhibition efficiency of PTOE reached 92.7％ at 1.0×10-3 mol/L.The potentiodynamic polarization curves of mild steel in sulphuric acid containing these compounds showed that both cathodic and anodic processes of steel corrosion were suppressed,and resistance of the steel increased with the increase in inhibitor concentration through the Nyquist plots of impedance expressed mainly as a capacitive loop with different compounds and concentrations.A linear fit to Langmiur isotherm was obtained between C/θ and C.The relationship between molecular structure of these compounds and the inhibition efficiency has been investigated by ab -initio quantum chemical calculations.