Study On The Corrosion Inhibition Performance Of Organic Nitrogen Heterocyclic Molecules On X65 Steel And Copper In Sulfuric Acid Solution

With the formulation of the 14 th Five-Year Plan and the 2035 long-term goal,resource conservation,ecological environment protection and sustainable development are becoming more and more important to our society as a whole.The development of efficient and environmentally friendly corrosion inhibitor molecules is an important research direction in metal corrosion and protection.In this thesis,through electrochemical techniques,surface topography analysis technology,element analysis technology and theoretical calculation,etc.methods,the corrosion inhibition performance and mechanism of organic nitrogen heterocyclic molecules on X65 steel and copper are explored,and provide experimental experience and theoretical guidance for the design and development of high-efficiency and green corrosion inhibitor molecules.The research content of this paper is as follows:(1)S-(benzo[d]thiazol-2-yl)(E)-2-(2-aminothiazol-4-yl)-2-(methoxyimino)ethan-ethioate(BTAE)molecules have a corrosion inhibition effect on X65 steel in 0.5 M sulfuric acid solution by electrochemical impedance and potentiodynamic polarization curves in the different temperatures,and the change of system temperature has a certain influence on the corrosion inhibition effect.The results of electrochemical experiments were verified by scanning electron microscope and atomic force microscope.Fitting the Langmuir adsorption isotherm model shows that BTAE molecules are mainly chemical adsorbed on the surface of the X65 steel electrode.Density functional theory(DFT)and molecular dynamics simulations show that BTAE molecules have multiple adsorption sites,including benzothiazole,aminothiazole and non-heterocyclic heteroatoms,which can make corrosion inhibitor molecules better adsorb on steel surface.(2)the corrosion inhibition performance of 6,7-di-(2-methoxyethoxy)-3,4-dihydroquinazolin-4-one(DME)and 6,7-Dimethoxy-3,4-dihydroquinazoline-4-one(DM)for copper in 0.5 M sulfuric acid solution was explored through electrochemical techniques.It was found that the longer the chain length of the substituent,the better the corrosion inhibition effect.The results of Langmuir adsorption isotherm model,quantum chemical calculation and molecular dynamics simulation show that the corrosion inhibitor molecules adsorb to the copper surface through chemical adsorption to prevent corrosive substances from corroding.The longer the chain length,the greater the protection range formed by parallel adsorption on the copper surface,the better the corrosion protection effect.The experimental results obtained are consistent with the theoretical calculation results.(3)The corrosion inhibition performance of 1-Dodecyl-3-Methyl-1H-Imidazolium Nitrate(DMIN)including long chain as corrosion inhibitor of copper was investigated in0.5 M sulfuric acid solution at different temperatures.The electrochemical results show that the corrosion inhibition efficiency increases as the concentration of DMIN increases.Theoretical calculations show that DMIN molecules are in a parallel adsorption configuration on the copper surface.Because of the longer alkyl chain,the coverage of the molecules on the copper surface is very large,which effectively blocks the contact between the corrosive medium and the copper surface.