Application of Xylopia aethiopica Seed Extract as Aluminium Alloy Corrosion Inhibitor in 0.75 M KOH Alkaline Solution

Corrosion  phenomena,  control  and  prevention  are  unavoidable  scientific  issues  that  should  be addressed due to increase of technological development. Aluminium (Al) is one of the most abundant elements found in the earth’s crust. The applications site of Almakes it to yield corrosion attack despite its corrosion resistance. The aim of alloying is to enhance the desired properties possessed by the Al. Plant extracts are rich source of naturally synthesised chemical compounds that can be extracted by simple procedure. The present study investigated the corrosion inhibition of Al alloy in 0.75 M  KOH  solution  at  room  temperature  using Xylopia  aethiopicaseed  extract.  The gravimetric technique was employed in the study. It was revealed that the presence of the spice extract in the test solution retards the corrosion rate.  The calculated inhibition efficiency from the inhibitor surface coverage was observed to increase linearly with the inhibitor concentration. The consideration of the Langmuir adsorption isotherm indicated that the mechanism of adsorption is Physisorption. Temkin isotherm models explained that there were lateral attractions of the inhibitor molecules on the Al alloy surface. Flory-Huggins isotherm model confirms that there is bulky displacement of water molecules on  the  metal  surface  due  to  the  presence  of  the  inhibitor  molecules.  This depicts that the  spice constituents clustered on the Al alloy surface preventing contact with the corrosive environment.

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