Surface morphology and corrosion behavior of pure aluminum and its alloys in aqueous sulfuric acid medium

Abstract

Aluminum and aluminum alloys are light materials with some of the preferences such as lightweight, high specific strength, good elasticity, and good workability that play an important role in today's modern and industrial world. The economic loss and environmental and safety problems are also the most concerning aspects of these materials. As a result, numerous studies are performed by the researchers to improve the overall environment throughout the materials world. That is why, in this study, the surface morphology and corrosion behavior of pure aluminum and its alloys, such as 7S10 and 7003H, were investigated in aqueous sulfuric acid medium through immersion process at different temperatures. Open‐circuit potential and potentiodynamic polarization techniques were used to evaluate the resistance to corrosion of pure aluminum and its alloys 7S10 and 7003H. The current density increased with increasing temperature in the case of the alloys, and pure aluminum showed the highest corrosion resistance properties. The surface roughness measurement was performed using atomic force microscope to find out the amount of roughness of the used materials before and after the immersion process. Surface roughness was higher on the alloys than in pure Al, which indicates that less corrosion was formed in pure Al than in the alloys. The surface morphology analysis was also carried out using scanning electron microscopic data. The results revealed that the alloy 7003H undergoes more corrosion than pure aluminum and 7S10 in sulfuric acid medium, which clearly indicates that pure aluminum has higher corrosion resistance than the alloys 7S10 and 7003H. The corrosion rate of the test materials decreased with increasing immersion time.

Corrosion Behavior of Pure Aluminum in the Simulated and Real Environments for Use as a Bipolar Plate Component in Polymer Electrolyte Membrane Fuel Cells

“…In simulated conditions, earlier studies have concerted on the corrosion features of Al in some dilute acidic solutions, such as sulfuric acid, hydrochloric acid, , sulfuric acid with hydrogen fluoride media, , sodium sulfate with sodium fluoride solution, − and seawater . It is known that the typical operating environment for the PEM FC includes a pH value in the range of 3 to 6, which is weakly acidic, whereas BPPs are typically handled on crevice corrosion by discharging the major anions such as F – , SO 4 2– , Cl – , etc., from the perfluoro-sulfonic acid membrane, and the temperature can reach up to 80 °C. − …”