Authors : Oluseyi O. Ajayi, Olugbenga A. Omotosho, Kolawole O. Ajanaku and Babatunde O. Olawore
Abstract: The deterioration behaviour of aluminum alloy in 2 M hydrochloric acid solution in the presence of Chromolaena odorata extract was investigated using gasometric technique. Aluminum alloy coupons of dimension 4 by 1 cm were immersed in test solutions of uninhibited acid and also those containing extract concentrations of 0.065, 0.098, 0.13 and 0.16 M at ambient temperature for 30 min. The volumes of hydrogen gas evolved as a result of the rate of reaction were documented and analyzed. The outcome revealed that maximum inhibitor efficiency which corresponds to the lowest corrosion rate was obtained at optimum inhibitor concentration of 0.16 M with reduction in the corrosion rate observed to follow in order of increasing extract concentration. The adsorption study further revealed that Freundlich isotherm best described the metal surface interaction with the extract phyto-chemicals with 20 min becoming the best exposure time for the phyto-chemicals to adsorb to the metal surface at all concentrations. Statistically modeling the corrosion rate yielded an important relationship suitable for estimating corrosion rate values, once concentration of the extract is known. Furthermore, the microstructural studies revealed that crack growth rate slowed down considerably at 0.16 M extract concentration and irregular intermetallic phases were more uniform as extract concentration increased.
Oluseyi O. Ajayi, Olugbenga A. Omotosho, Kolawole O. Ajanaku and Babatunde O. Olawore, 2011. Degradation Study of Aluminum Alloy in 2 M Hydrochloric Acid in the Presence of Chromolaena odorata. Journal of Engineering and Applied Sciences, 6: 10-17.