Study Of Benzotriazoles Compounds On The Corrosion Inhibition Mechanism Of Typical Metal Alloys

It is important to protect metal materials from being corroded because chloride ion erosion will happen when the materials are explored to atmospheric environment.There are multiple ways to improve the corrosion resistance of the materials.Corrosion inhibitor technology is one of the most important means of anti-corrosion,which has been widely used in atmospheric environment due to it easy operation,low cost and obvious effects.Among the corrosion inhibitors,organic ring compounds,containing hetero atoms of nitrogen,sulfur,oxygen and so on,can more easily adsorb on metal surface,which are capable to effectively isolate possible active site on the metal surface from the corrosive medium and inhibit metal corrosion,prolonging their service life.Therefore,this type of corrosion inhibitors on the corrosion mechanism of metal research has important theoretical significance and application value,whose excellent corrosion effect has become one of hot topics in the study of organic corrosion inhibitors.Benzotriazole(BTA)and methyl benzotriazole(TTA)are typical nitrogenous organic compounds.In this thesis,the two kinds of compounds are respectively employed to work as a corrosion inhibitor for galvanized steel and pure copper in 5.0 mM NaCl solution.The protective abilities of the inhibitors are investigated by potentiodynamic polarization curves(PC),electrochemical impedance spectroscopy(EIS),immersion test,scanning electron microscope(SEM)and atomic force microscopy(AFM),We also research the corrosion inhibition mechanism of the two compounds.The results indicate that both BTA and TTA increase the corrosion resistance of the galvanized steel and copper.The inhibition efficiencies reach maximum values of 97.9%and 98.2%when the concentration of BTA and TTA are 0.1 mol/L and 10.0 mmol/L,respectively.When the polarization curves of the galvanized steel and the copper are measured in a corrosion solution containing BTA or TTA,both the cathodic current density and the anodic current density reduce markedly.The phenomenon indicates both the cathodic and the anodic electrochemical processes are inhibited;in addition,both BTA and TTA are mixed inhibitors.SEM and AFM analyses confirm that the surface corrosion of galvanized steel and copper have been inhibited by these inhibitors.We consider that the corrosion inhibition can be attributed to the absorption of the inhibitors and forming a passivation layer on the metal surface.And the corresponding adsorption process follows Langmuir’s isothermal adsorption model.