Investigations Of Pyridazine Derivatives As Corrosion Inhibitors On Copper In 0.5M H₂SO₄ Medium

In order to alleviate the growing concern of environmental protection,developing green,environment-friendly and efficient anticorrosive agent for metal materials in corrosive environment is significant.In this thesis,three pyridazine derivatives molecules were used as effective corrosion inhibitors of Cu in 0.5M sulfuric acid solution,and the adsorption of organic corrosion inhibitor molecules on the surface of copper/solution and the corrosion inhibition performance of corrosion inhibitor molecules on metal copper were deeply discussed by systematic electrochemical tests and surface analysis experiments.Combined with theoretical calculation,the corrosion inhibition mechanism of the inhibitor molecules on the copper surface was further revealed.This work may provide additional insights into the use of high-performance inhibitors for Cu.The main research work of this thesis is as follows:(1)The corrosion inhibition effect of pyridazine derivative(CPD)on copper in0.5M H₂SO₄ solution was studied by electrochemical test,surface analysis and computer simulation.And the results showed that CPD was a modest cathodic-type corrosion inhibitor.At 298 K,the inhibition efficiency(?)increases first and then decreases with the increase of the open circuit time,and the maximum inhibition efficiency is reached at 0.5h.With the increase of sulfuric acid concentration,the inhibition efficiency?gradually decreases,and the best inhibition effect is achieved when the concentration of sulfuric acid is 0.25M.CPD fits the Langmuir isotherm adsorption model,and the value of(35)G⁰_ads is around-40 k J/mol,to show that the CPD adsorption on the surface of the copper and the mixture of chemical adsorption on adsorption model.Quantum chemistry calculation and molecular dynamics simulation further proved that CPD as a corrosion inhibitor of copper in sulfuric acid solution has excellent corrosion inhibition.(2)A novel pyridazine derivative(EPD)was synthesized by a simple organic synthesis method,and the synthesis method was applied for patent protection.Electrochemical results show that EPD,as a modest cathodic corrosion inhibitor,can effectively inhibit the corrosion of copper in 0.5 M sulfuric acid solution.At the same temperature,the inhibition efficiency increases with the increase of concentration.However,at different temperatures,for the same concentration,the corrosion inhibition efficiency decreases slightly with the increase of temperature.In addition,the XPS and infrared analysis results showed that EPD molecules stably adsorbed on the copper surface to form protective film through N-Cu bond,Cu-S bond and other chemical bonds.At all test temperatures,the EPD meets the Langmuir isotherm adsorption model,and the value of(35)G⁰_ads is about-40 k J/mol,indicating that EPD in adsorption on the surface of the copper is mainly chemical adsorption model.(3)The corrosion inhibition of copper by CMP in 0.5M H₂SO₄ solution and the mechanism of corrosion inhibition were studied by electrochemical method,and the morphology of copper was observed by scanning electron microscope and atomic force microscope.Tafel curve shows that CMP can effectively inhibit the corrosion of copper in sulfuric acid solution under all test temperature conditions,and it is a mixed corrosion inhibitor.With the increase of temperature,the corrosion inhibition efficiency decreases.EIS test shows that the corrosion inhibition efficiency increases with the increase of concentration at the same temperature.However,at different temperatures,for the same concentration,the corrosion inhibition efficiency decreases with the increase of temperature.The results of EIS test are in good agreetment with the Tafel curve.Besides,CMP is in line with the Langmuir isotherm adsorption model at all test temperatures,and the values of(35)G⁰_ads are less than-40 k J/mol,indicating that CMP and copper surface is the chemical adsorption on the interaction.Finally,quantum chemistry calculation and molecular dynamics simulation further verified that CMP was closely adsorbed on Cu(111)surface in a parallel way,which confirmed its excellent corrosion inhibition performance in sulfuric acid solution...