Effects of polyethylene glycol (PEG) on the corrosion inhibition of mild steel by cerium nitrate in chloride solution

•The corrosion rate of mild steel decreased gradually with increasing the content of cerium in 0.1 M NaCl.•The corrosion resistance was optimal with a cerium nitrate content of 600 mg L−1 in 0.1 M NaCl.•Combined additions of cerium nitrate and of PEG significantly increased the corrosion resistance of mild steel in 0.1 M NaCl.•Corrosion inhibition for 30 days of immersion in 0.1 M NaCl with Ce + PEG was procured by a thin a barely cracked film. In this study, cerium was investigated as an inhibitor to improve the corrosion resistance of ASTM A915 mild steel in 0.1 M NaCl solution. Increasing the Ce3+ concentration up to an optimum level of 600 mg·L−1 (or 1.4 · 10−3 M) sharply decreased the corrosion rate (Icorr). However, the beneficial effect of cerium was lost after short immersion times at room temperature. In contrast, the addition of polyethylene glycol (PEG) to the cerium nitrate containing NaCl solutions enhanced protection through the formation of stable corrosion products and the decrease of cracks in the film formed on the surface of mild steel.