Green inhibition of carbon steel corrosion by fish oil in hydrochloric acid medium

Corrosion is a major problem of the  destruction of various materials, especially metals. The highest effect of corrosion processes increased during pollution. The environmental toxicity of organic corrosion inhibitors has prompted the search for green corrosion inhibitors as they are biodegradable, do not contain heavy metals or other toxic compounds and readily available and renewable. The effect of fish oil as a green inhibitor of carbon steel corrosion has been investigated in a 1 M hydrochloric acid solution using polarization curves, electrochemical impedance spectroscopy (EIS) and gravimetric techniques. The obtained results reveal that fish oil effectively inhibits the corrosion of carbon steel. The highest inhibition efficacy value is 91.82% obtained by potentiodynamic polarization and 92.96% by electrochemical impedance spectroscopy at the maximum concentration tested. The inhibition efficiency increased with increasing concentration of tested oil, although he's remainder stable with increasing temperature. The polarization curves show that the tested oil can be considered as a mixed type inhibitor and that the absorption of the inhibitor on the carbon steel electrode obeys the Langmuir isotherm. The EIS results indicate that changes in impedance parameters are related to the adsorption of fish oil on the surface of the alloy.