Corrsion Inhibition of Cinnamomum Camphora Seeds Extract for A3 Steel in 5% H2SO4 Solution

The inhibition of cinnamomum camphora seeds extract(CCSE) on A3 steel in 5% H2SO4 solution at 25 ℃ was studied by methods of weight loss、potentiodynamic polarization curves、electrochemical impendance spectroscopy (EIS).The results showed that CCSE was a good corrosion inhibitor, and maximum inhibition efficiency was up to 84.01% at a concentration of 15 g/L at 25 ℃.The inhibitive mechanism was proposed from the adsorption viewpoint and the adsorption of CCSE on A3 steel surface obeys Langmuir adsorption isotherm.The experimental data were treated with related equations to calculate the adsorption Gibbs free energy ΔG, and the inhibitive mechanism was discussed in detail according to the parameters.The value of ΔG was between -20 kJ/mol and 0 kJ/mol, so its adsorption was physical adsorption.Polarization curves reveal that CCSE behaves as a mixed-type corrosion inhibitor.