Garlic Extract as an Environmentally Corrosion Inhibitor of API X60 Carbon Steel and 316L Stainless Steel in Sulphuric Acid

The high toxicity of industrial metal corrosion inhibitors raises various environmental and health problems. Thus, the study of metals and alloys corrosion inhibition, in acidic media, by eco-compatible organic compounds, has become a very attractive research field. In this paper, garlic ( Allium Sativum ) extract inhibition efficiency (IE) against API X60 carbon steel (CS) and 316L stainless steel (SS) corrosion, in a 1 M sulphuric acid (H 2 SO 4 ) solution, has been investigated using electrochemical techniques, including potentiodynamic polarization (PPD) and electrochemical impedance spectroscopy (EIS). The experimental results showed the remarkable corrosion inhibitive performance of garlic extract (GE). The corrosion IE, which depends on the inhibitor concentration, increased up to 90%, for SS, and 67% for CS, as shown from the PPD tests. EIS analysis showed that the corrosion resistance (CRST) was increased in the medium with GE, indicating the properties improvement of the passive films formed on the steels surfaces.