Corrosion Resistance of FeCrMnAlCux High-Entropy Alloys in 0.5 mol/L H2SO4 Solution
This study employed vacuum arc melting technique to fabricate FeCrMnAlCux(x=0,0.5,1.0,1.5,2.0)high-entropy alloys.The phase structure and microstructure of the alloys before and after corrosion were characterized using XRD,SEM,and EDS.The corrosion behavior of the alloys in 0.5 mol/L H2SO4 solution was analyzed through potentiodynamic polarization curves,EIS,XPS,and immersion tests.The results indicate that the addition of Cu promotes the formation of the fcc phase in the alloy,transforming the single bcc structure into the mixed bcc+fcc dual-phase structure.The high-entropy alloys with five different composition exhibit a typical dendritic morphology.With increasing the Cu content,the grains are gradually refined,and the microstructure becomes more uniform.The FeCrMnAlCui.5 high-entropy alloy has the highest corrosion potential(-0.363 V)and the lowest corrosion current density(2.148x10-5 A/cm2).The corrosion resistance of the alloy is initially improved and then deteriorates with increasing the Cu content.At x=2.0,the corrosion potential decreases to-0.394 V,the current density increases to 2.865×10-4 A/cm2,yet its corrosion resistance is still superior to that of the alloy without Cu addition.After corrosion,a composite oxide protective film forms on the cross-section of the alloy,effectively reducing its corrosion rate in 0.5 mol/L H2SO4 solution.
high-entropy alloysmicrostructurecorrosion resistanceoxide film
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