Influence of some plant leaves extracts on corrosion inhibition of aluminium in alkaline medium

Abstract

In this thesis, the extracts of some leaves of Adathoda vasica (adathodai), Aegle marmelos (vilvam), Centella asiatica (vallarai), Cyanodon dactylon (arukampull) and Solanum trilobatum (thuthuvalai) are collected and evaluated for their corrosion inhibition performance for aluminium in 1N NaOH solution using weight loss, gasometric, potentiodynamic polarization and AC-impedance studies to find out the inhibition efficiency of the inhibitors. From the electrochemical studies, the mode of inhibition mechanism of the natural inhibitors are proposed. While assessing the performance of the inhibitors, the effect of inhibitor concentrations and temperatures are also to be studied. The appropriate adsorption isotherm has proposed to explain the experimental observations. The Hydrogen Permeation studies in the absence and presence of inhibitors are performed to know the extent of corrosion inhibition and the percentage decrease in permeation current. Surface examination studies on the aluminium in the absence and presence of inhibitors are made for the confirmation of film formation as well. From the above studies, it is observed that all the prepared leaves extracts are able to reduce the dissolution of aluminium in 1N NaOH solution in the presence of inhibitors, and the order of corrosion inhibition is as follows; Aegle marmelos (vilvam) gt Solanum trilobatum (thuthuvalai) gt Adathoda vasica (adathodai) gt Cyanodon dactylon (arukampull) gt Centella asiatica (vallarai).