Efficient and long-lasting corrosion inhibition mechanism of an anionic surfactant on AZ91D Mg alloy in oxalic acid solution

Abstract

The efficient and long-lasting corrosion inhibition mechanism of bis(2-ethylhexyl) sulfosuccinate sodium (AOT) on AZ91D Mg alloy in oxalic acid solution were studied by electrochemical methods, surface techniques, theoretical calculations and simulations. The findings demonstrated that AOT was an effective and long-lasting corrosion inhibitor, the corrosion inhibition rate of 6.75 mM AOT was 89.84 % and raised in corrosion inhibition effectiveness with increasing soaking duration. The adsorption of AOT followed Langmuir adsorption isotherm and belonged to physical and chemical mixed adsorption. The polar sulfonyl group of AOT gradually almost vertically adsorbed on its surface to produce a uniform, dense, and thick protective layer to inhibit its corrosion, and the hydrophobicity of the alkyl chain of AOT repelled corrosive medium.

Keywords

• AZ91D Mg alloy
• Oxalic acid
• AOT
• Corrosion inhibitor
• Long-lasting