Corrosion Inhibition Of Stainless Steel And Carbon Steel By Amino Acid And Melamine

Carbon steel and stainless steel are the most widely used iron alloys.They will be corroded by electrochemical reaction in the corrosive medium.The corrosion inhibition properties of organic compounds such as amino acids and melamine for 304 stainless steel and 1045 carbon steel in PCMs solutions were studied by electro-chemical techniques.The inhibition mechanism of inhibitors was theoretical studied by quantum chemical calculation and molecular dynamics simulation..The corrosion inhibition of methionine and proline on 304 stainless steel in phase change materials(PCMs)solution was studied by Electrochemical techniques.Results showed that all the amino acid inhibitors can protect 304 stainless steel from corrosion in PCMs solution.The methionine/proline compounded inhibitor had the highest inhibition efficiency.Scanning electron microscopy(SEM)was used to investigate the morphology of the corroded stainless steel.The inhibition mechanism was theoretically investigated through the quantum chemical calculation and dynamic simulationThe corrosion protection performance of cysteine(Cys)and melamine(Mel)on 1045 carbon steel(CS)in phase-change-materials(PCMs)solution have been studied by electrochemical impedance spectroscopy(EIS),Potentiodynamic polarization measure-ments,SEM and X-ray photoelectron spectroscopy(XPS).EIS results showed that Cys and Mel can protet CS from corrosion in PCMs solution,and Cys compounded Mel inhibitor can increase the corrosion protection efficiency,even achieved 96.3%.Potentiodynamic polarization measurements results confirmed that all Cys,Mel and Cys/Mel compound inhibitor can protect CS from corrosion.SEM micrographs showed that all three inhibitors can prevent the corrosion of CS in PCMs solution.XPS results showed that the Cys and Mel can adsorb on CS surface to form inhibition films,thereby inhibited CS corrosion in PCMs solution.Quantum chemical calcu-lations and molecular dynamics simulation were used to theoretically investigate the inhibition mechanism.The corrosion inhibition properties of histidine and its derivatives SAMs for carbon steel and stainless steel in PCMs solution were investigated.Quantum chemical calculations and molecular dynamics simulations demonstrate that the three molecules are feasible as corrosion inhibitors for steel materials.EIS and potentiodynamic polarization curves results showed that the inhibition performance of histidine and its derivatives SAMs on stainless steel is much greater than its corrosion inhibition performance for carbon steel.And the three kinds of SAMs were mixed-type inhibitors on the carbon steel surface,and they were anode-type inhibitors on the stainless steel surface.SEM characterization confirmed the inhibition performance of the inhibitor.XPS characterization results showed that the high inhibition performance of histidine and its derivative molecules on stainless steel was because the organic molecules not only form coordination bonds with iron atoms,but also with the chromium atom and the nickel atom on stainless steel surfaces.,which makes the SAMs more dense and perfect.