Corrosion inhibition of LY12CZ aluminum alloy by 3‐pyridyl‐4‐amino‐1,2,4‐triazole‐5‐thiol and its cerium nitrate compound.

The inhibition effect of 3‐pyridyl‐4‐amino‐1,2,4‐triazole‐5‐thiol (C7H7N5S) and its cerium nitrate (Ce(NO3)3) compound on the corrosion of LY12CZ aluminum in 3.5% NaCl was investigated by means of potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). Results showed that the inhibition efficiency reached 77.61% at 0.8 g L−1 concentration and was found to increase with increasing concentration of C7H7N5S. C7H7N5S is a mixed type inhibitor. The desorption onset potential was obtained from differential polarization curve. EDS data indicated that C7H7N5S can adsorb on the S phase and inhibit the cathode action of the S phase. Both kinetic and thermodynamic parameters were calculated and discussed. The adsorption of C7H7N5S on aluminum surface was found to obey the Langmuir adsorption isotherm, and being both physisorption and chemisorption. C7H7N5S and Ce(NO3)3 have an additive inhibition effect. The additive action improved the surface coverage of the aluminum and the stability of the adsorbed layer. [ABSTRACT FROM AUTHOR]