Corrosion inhibition of 57s aluminium Alloy as anode material in NAOH By ZNO and polyaniline

Abstract

The inhibition of aluminium corrosion in alkali solutions is of newlinecontinued interest In alkali solutions corrosion of aluminium occurs at a high newlinerate accompanied by hydrogen evolution Various inhibitor formulations newlineaddition agents and complexing agents were added in solution to minimize newlinecorrosion The present investigation deals with the development of newer newlineinhibitor based on polyaniline In this investigation the inhibitive behaviour newlineof zinc oxide and various concentrations of polyaniline for 57S aluminium newlinealloy in 2M NaOH has been studied using gravimetric impedance and Tafel newlinepolarization techniques Besides the anode performance of polyaniline coated newlinespecimens of 57S grade aluminium with zincated specimen of 57S grade newlinealuminium has been studied Corrosion inhibition of 57S aluminium in 2M NaOH by 2M ZnO newlinehas been studied by the electrochemical techniques such as impedance linear newlineand Tafel polarization methods The charge transfer resistance Rct double newlinelayer capacitance Cdl have been found out from impedance behaviour of 57S newlinealuminium individually from Nyquist plots in the presence of 2M ZnO It is newlineobserved that the Rct value increases with subsequent decrease in Cdl values as newlinethe concentration of inhibitors is increased It shows that the more adsorption newlineof inhibitors on 57S aluminium surface takes place which results in increased newlineinhibition efficiency newline newline