Protection Efficiency of Triethanolamine Decanedioate as a Water-Soluble Corrosion Inhibitor for Steel in Metalworking Fluids

Abstract

Triethanolamine carboxylates, particularly triethanolamine decanedioate (TEA·C10), are widely employed as corrosion inhibitors for steel in aqueous solutions used in metalworking applications. This compound inhibits corrosion reactions at both the anode and cathode through physical and chemical adsorption onto the steel surface, forming a protective corrosion-resistant film. It is also a non-volatile organic compound with relatively low toxicity and is cost-effective. The corrosion inhibition mechanism and anticorrosion efficiency of TEA·C10 were investigated by analyzing the surface corrosion behavior of Q215 mild steel in 0.1 M NaCl solution compared with triethanolamine (TEA). The IP287 test results indicate that rust area of TEA·C10 on filter paper are significantly reduced compared to TEA. The results from potentiodynamic polarization testing show that TEA·C10 exhibits a lower corrosion rate compared to TEA, with inhibition efficiencies of 97.87% at a concentration of 2.4 M. Consistent with the EIS test results, it was also show that the presence of TEA·C10 reduces the double-layer capacitance during the corrosion process, leading to a more significant decrease in charge transfer resistance, resulting in a corrosion inhibition efficiency of up to 98.66% at a concentration of 2.4 M.