Fabrication, Characterization, and Corrosion Protection of Hot Dip Aluminized Coatings for Steel Using Discarded Soda Cans

Abstract

Corrosion, which seriously affects the quality and functionality of steel can be reduced by hot dip aluminising which involves dipping substrate to a molten aluminium bath. Thus, this study aimed to produce a hot dip aluminised coating for steel-using discarded soda cans. A total of 80 steel nails with a length of 65.62±0.56 mm were used wherein 40 nails were intended for the hot-dipaluminising process at 650-700°C with an average coating mass and thickness of 547g/m2 and 170 μm, respectively, with a density of 2.627g/cm3following ASTM standards. Compared to the non-coated setups, the fabricated aluminium coating reduced 0.178g and 0.092g of corrosion products accumulation after immersions on H2O2and NaCl solutions for 7days and 4weeks, respectively. Optical analysis of surface and cross-sections of the coated samples showed less pitting and corrosion products. Aluminium coating tends to pit that starts from small cracks and fractures when immersed in the corrosive medium. Moreover, scanning electron microscopy showed that the coated nail sample experienced minimal corrosion in the form of thin cracks compared to non-coated nails, which had a relatively rough surface as a result of heavy corrosion. Also, a t-test showed a significant difference between the accumulated corrosion products’ weights of coated and non-coated setups after immersing in NaCl (t=-13.801; p=0.000) and H2O2(t=-31.005; p=0.000) wherein less corrosion product was obtained by the coated set-up (x=0.036 (H2O2) and x=0.028 (NaCl)). Thus, the results proved that the produced aluminized coating from waste soda cans provides a significant corrosion protection on the steel substrates.