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Improved corrosion inhibition of calcium disodium EDTA for mild steel in chloride-contaminated concrete pore solution

2023; Elsevier BV; Volume: 140; Linguagem: Inglês

10.1016/j.cemconcomp.2023.105075

1873-393X

Zhicheng Liu, Fengrui Zhang, Xuan Li, Danqian Wang,

Concrete and Cement Materials Research

The corrosion inhibition of EDTA-Ca for mild steel in chloride-contaminated concrete pore solution, with EDTA-Na as comparison, was investigated via several electrochemical methods and surface characterizations. Results show that corrosion inhibition efficiency of EDTA-Ca is higher than that of EDTA-Na. Corrosion inhibition efficiency increased with an increase in EDTA-Ca concentration while decreased with the increased EDTA-Na concentration. EDTA-Ca adsorbs physiochemically on surface of mild steel which obeys Langmuir isotherm, while adsorption of EDTA-Na is physical obeying Freundluich isotherm. A much thinner and more compact oxide film with higher Fe2+ content formed in the presence of EDTA-Ca compared to EDTA-Na. The availability of coordinate bonds for chelation in EDTA-Ca or EDTA-Na plays a critical role in determining the corrosion inhibition efficiency.