Degradation Study of Aluminum Alloy in 2 M Hydrochloric Acid in the Presence of Chromolaena odorata

The deterioration behaviour of alwninwn alloy in 2 M hydrochloric acid solution in the presence of Chromolaena odorata extract was investigated using gasometric technique. Alwninwn alloy coupons of dimension 4 by 1 em were immersed in test solutions of rminhibited acid and also those containing extract concentrations o£0.065, 0.098, 0.13 and 0.16 Mat ambient temperature for 30 min. The volllllles of hydrogen gas evolved as a result of the rate of reaction were docwnented and analyzed. The outcome revealed that maximwn inhibitor efficiency which corresponds to the lowest corrosion rate was obtained at optimwn inhibitor concentration of 0.16 M with reduction in the corrosion rate observed to follow in order of increasing extract concentration. The adsorption study fwi:her revealed that Frenndlich 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. Fwi:hermore, the microstructural studies revealed that crack growth rate slowed do considerably at 0.16 M extract concentration and irregular intermetallic phases were more mriform as extract concentration increased.