Corrosion Inhibition Of 1045 Carbon Steel By Phytic Acid And Its Complex Inhibitor

Due to the plasticity of carbon steel is high and the mechanical is strength,carbon steel which occupies a very important position in the national economy is widely used in all industries.According to the amount of carbon content,it can be divided into low carbon steel?WC?0.25%?,medium carbon steel?WC:0.25%—0.6%?and high carbon steel?WC>0.6%?.Carbon steel is also a kind of alloy.So the heterogeneity of the internal structure and composition makes carbon steel easy to electrochemical corrosion in the corrosive medium.Based on carbon steel easy to corrosion,with phytic acid as the main distribution of corrosion inhibitors for carbon steel in 0.5 mol·L^-1 HCl solution and phase change storage material as corrosive medium was studied,and the corrosion mechanism is analyzed.Experiments with phytic acid and benzyl trimethyl ammonium bromide as a corrosion inhibitor respectively for carbon steel is studied at 0.5 mol·L^-1 HCl solution,AC impedance and polarization curves showed that the two molecules are corrosion effect,but the inhibition efficiency is not high.The electrochemical tests showed that the inhibition efficiency of the two molecules was 90.6%.Quantum chemical calculation a nd molecular dynamics simulation show that the aromatic ring structure and phosphate groups are the main active sites on the surface of carbon steel.The experiments study the phytic acid compound with benzyl trimethyl ammonium bromide for 1045 carbon steel corrosion inhibition in the phase change storage material.Adopted an hour soaking as evaluation standard,by ac impedance spectroscopy and potentiodynamic polarization curve test results show that the two molecules are corrosion effect,two molecular compound with corrosion inhibition efficiency can reach 53.94%.It also proved that phytic acid,benzyl trimethylammonium bromide and the combination of both were composite inhibitor.The SEM characterization shows that the pore corrosion of Cl^-is the main factor for the corrosion of carbon steel in the phase change storage material,and it can be clearly seen that the surface corrosion of carbon steel is different when there is no corrosion inhibitor.In order to study the corrosion mechanism,the estab lishment of a complex system of molecular dynamics simulation,can be intuitive to see phytic acid and benzyl trimethyl ammonium bromide both molecules as planar adsorption on carbon surface.Phytic acid compound with histidine are studied in the experiments of 1045 carbon steel corrosion inhibition in the phase change storage material.AC impedance and potentiodynamic polarization curves show that the effect of phytic acid and histidine are corrosion,histidine separate corrosion efficiency than phytic acid alone do the efficiency of corrosion inhibitor.However,when the combination of the two can improve the inhibition efficiency,the maximum corrosion efficiency is 60.25%,but there is also a competitive adsorption relationship between the two.SEM showed that the corrosion inhibitor did have a corrosion inhibition effect.Quantum chemical calculation and molecular dynamics simulations show the molecular size has a certain influence on efficiency of the corrosion inhibitor in the high concentration of ions in the solution.The histidine with smaller molecular sizes can fill in the corrosion film clearance formed by phytic acid molecules,so as to improve the efficiency of the corrosion.