Plant Extracts as Corrosion Inhibitors : Studies on the inhibitory effect of plant extracts on corrosion of mildsteel in Hydrochloric acid medium

Mild steel suffers from severe corrosion in aggressive medium of acids during pickling processes. The use of inhibitors is one of the most effective and practical methods of protection of corrosion of metals in acid medium. Hydrochloric acid is widely used for pickling, descaling and chemical cleaning processes of mild steel. About 90% of pickling problems can be solved by introducing appropriate picking inhibitor to the medium. Owing to strict environmental legislation the emphasis is being focused on development of naturally occurring substances as corrosion inhibitors. Due to ease of application, cost effectiveness, environmentally safe, soluble and highly stable nature in acidic solutions, in this study, the inhibitory effect of six plant extracts Adathoda vasica, Aegle marmelos, Centella asiatica, Eclipta alba, Ocimum sanctum, Solanum trilobatum on the corrosion of mild steel in 1N hydrochloric acid was investigated by Weight loss method, Gasometric method, Potentiodynamic Polarization method and Impedance method and found to be effective corrosion pickling inhibitors.