Comparative Electrochemical Study of Corrosion Behavior of AA 5052 and AA 5754 Aluminum Alloys in Chloride, Boric Acid, and Sulfate Media

In this research, the corrosion behavior of AA5052 and AA5754—candidate materials for nuclear fuel assemblies in research and test reactors—was investigated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) in three electrolytes: NaCl, H 3 BO 3 , and Na 2 SO 4 . The surface morphology of AA5052 and AA5754 samples before and after corrosion testing was examined using scanning electron microscopy (SEM). In NaCl electrolytes (0.05 M and 0.005 M), both the corrosion current density (i corr ) and passivation current density (i pass ) of AA5052 were higher than those of AA5754. For AA5754, the passivation potential range (ΔE pass ) decreased from 0.60 V to 0.16 V when the NaCl concentration increased from 0.005 M to 0.05 M. In contrast, increasing the NaCl concentration did not significantly affect the ΔE pass of AA5052; the passivation range shifted only from 0.59 V to 0.44 V. Polarization tests in boric acid solutions (1000 ppm, equivalent to 0.0162 M, and 3000 ppm, equivalent to 0.0485 M) indicated that both AA5052 and AA5754 undergo uniform corrosion. The alloys exhibited their lowest corrosion rates in boric acid, with i corr ranging from 10 -5.2 to 10 -6.1 A/cm². The behavior of the two alloys differed markedly in Na 2 SO 4 electrolyte. In Na 2 SO 4 , the corrosion rate of AA5754 (i corr =10 -1.3 A/cm²) was significantly higher than that of AA5052 (i corr =10 -5.4 A/cm²). Another notable difference was the wider ΔE pass observed for AA5754 in Na 2 SO 4 . This divergence in behavior is attributed to the higher chromium content in AA5052, the higher magnesium content in AA5754, and the influence of alloy composition on passive layer stability.