Corrosion Inhibition Of Aluminum Alloys By 3-pyridyl-4-amino-1,2,4-triazole-5-thiol And Its Compounds

Aluminum and its alloys are extensively used in domestic and industrial applications due to their exceptional physical and chemical properties and metallurgical properties.However,when they are exposed to a solution containing aggressive ions such as Cl^-,the naturally formed oxide film on the aluminum surface will lose its protective ability,which exacerbates the corrosion of aluminum alloy,especially pitting corrosion.It is very likely to cause rapid failure of materials,which is extremely harmful.The use of corrosion inhibitor is the most economical,efficient and convenient way to inhibit corrosion.In recent years,high-efficiency and environmentally-friendly organic corrosion inhibitors have received increasing attention,such as triazoles,imidazoles,pyridines,and thiol compounds.In this work,3-pyridyl-4-amino-1,2,4-triazole-5-thiol?C₇H₇N₅S?was synthesized and compounded with cerium nitrate?Ce?NO₃?₃?and potassium permanganate?KMnO₄?.The inhibition effect and mechanism of C₇H₇N₅S and its compounds for 1060 pure aluminium and LY12CZ aluminum alloy in 3.5%NaCl were investigated by means of potentiodynamic polarization?PP?,electrochemical impedance spectroscopy?EIS?,scanning electron microscopy?SEM?and energy dispersive spectrometer?EDS?.In addition,the mechanism of corrosion inhibition was deeply studied and discussed by calculating the adsorption thermodynamics and kinetic parameters,which provides scientific basis for the study of reducing the corrosion of aluminum alloy in strong chlorine medium.The results show that:C₇H₇N₅S can effectively inhibit the corrosion of 1060 pure aluminum and LY12CZ aluminum alloy in 3.5%NaCl solution.The inhibition efficiency of C₇H₇N₅S on 1060 pure aluminum and LY12CZ aluminum alloy is higher at concentrations of0.4 g/L and 0.8 g/L,respectively,both exceeding 70%,and the inhibition efficiency of C₇H₇N₅S on LY12CZ aluminum alloy is found to increase with increasing concentration of C₇H₇N₅S.C₇H₇N₅S is a mixed type inhibitor.The adsorption of C₇H₇N₅S on the surface of the two aluminum alloys obeys the Langmuir adsorption isotherm,and being both physisorption and chemisorption.C₇H₇N₅S and Ce?NO₃?₃ have a synergistic inhibition effect on 1060 pure aluminum.The inhibition efficiency reaches 88.2%when the optimum concentration of the two corrosion inhibitors is reduced by half.The two inhibitors promote each other,improving the surface coverage of pure aluminum and the stability of the adsorbed film.C₇H₇N₅S and KMnO₄ exert an additive inhibition effect on the pure aluminum by geometric coverage mechanism,and the improvement of the corrosion inhibition effect is the result of a simple addition of the two corrosion inhibitors.C₇H₇N₅S and Ce?NO₃?₃ have an additive inhibition effect on LY12CZ aluminum alloy.The additive action is beneficial to the adsorption of C₇H₇N₅S on the S phase and inhibits the cathode action of the S phase.C₇H₇N₅S and KMnO₄show an antagonistic effect on LY12CZ aluminum alloy in 3.5% NaCl solution.