Effect of Chitosan on the Corrosion Inhibition for Aluminium Alloy in H2SO4 Medium

Abstract

Aluminum AA5052 is an inexpensive and lightweight metal that has been used in a variety of applications, including the Bipolar Plate in Proton Exchange Membrane Fuel Cells (BPs PEMFC). The alloy has good electrical conductivity and low corrosion. Corrosion rate (CR) increases during PEMFC operation with increasing temperature. Inorganic dyes, such as chromate, are commonly used to reduce metal corrosion. Unfortunately, they are toxic and have a negative impact on the environment. Chitosan, which is a green, cheap, non-toxic, and environmentally friendly organic solvent, can be used to solve this problem. Electrophoretic Deposition (EPD) technique was used to coated the surface of AA5052 with chitosan. CR was measured using electrochemical and weight loss methods (in 0.5 M H2SO4). The best research results are as follows. The lowest CR values were obtained at the EPD time of 20 min at a chitosan concentration of 0.5% wt. The results of the study using the weight loss method indicated that after soaking for 72 h, the chitosan inhibitor can reduce the corrosion rate (CR) with an inhibitor efficiency of 87.89%, while the electrochemical method obtained a higher efficiency of 95.12%. An increase in temperature will result in a decrease in the efficiency of the inhibitor. Testing with SEM-EDX, after being coated with chitosan inhibitor, the metal surface looks smoother and the Al composition is reduced and it is detected that there is adsorption of O, N and S elements that coated the metal to form insoluble complex compounds, so the corrosion rate decreases.