The use of a thiadiazole derivative to inhibit mild steel corrosion in 1 M HCl solution: Electrochemical and surface active aspects

• M.D. Plotnikova, M.G. Shcherban, A.B. Shein, A.S. Sofronov and P.G. Melnikov

Perm State National Research University, st. Bukireva 15, 614068, Perm, Russian Federation

Abstract: Some aspects of mild steel corrosion in 1 M hydrochloric acid with addition of 1,3-DPTA in the corrosive system were studied by weight loss and electrochemical methods (potentiodynamic polarization measurements and electrochemical impedance spectroscopy) and also by contact angle and surface tension measurements. N-(1,3-dithiolan-2-ylidene)-5-phenyl-1,3,4-thiadiazole-2-amine (1,3-DPTA) has high inhibitory effect on the cathodic and anodic reactions on steel in HCl solutions. To determine the mechanism of inhibition of 1,3-DPTA, different adsorption isotherms including Langmuir, Freundlich, Temkin and Redlich-Peterson model were studied. The adsorption of 1,3-DPTA is described as a complex process of interaction of inhibitor molecules with the steel surface linearized in the coordinates ln(θ/(1–θ))=f(lnC). The corrosion rate decreased with the addition of 1,3-DPTA due to the formation of a hydrophobic film. This process is proven by measuring the contact angles of water after the samples are immersed in aggressive media with inhibitor for 24 hours. The hydrophobization of the steel surface increases with increase in the inhibitor concentration.

Keywords: mild steel, acid corrosion inhibitor, thiadiazole, potentiodynamic polarization, contact angle, surface energy, electrochemical impedance, adsorption

Int. J. Corros. Scale Inhib., 2023, 12, no. 4, 2362-2374
doi: 10.17675/2305-6894-2023-12-4-48

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