Corrosion Behavior of AlCoCrFeNi2.1 Eutectic High-Entropy Alloy in Sulfuric Acid Solution
Several high-entropy alloys(HEAs),such as single-phase bcc HEA with high strength and fcc with high ductility have been developed over the past few decades.Eutectic HEA(EHEA),such as Al-CoCrFeNi2.1,consists of both fcc and bcc microstructure,imparting excellent mechanical properties.The recent research on AlCoCrFeNi2.1 EHEA primarily focuses on its mechanical properties.However,corro-sion resistance of AlCoCrFeNi2.1 EHEA is rarely discussed,which is crucial for the application of new ma-terials.This work investigates the corrosion behavior of AlCoCrFeNi2.1 EHEA in 0.05 mol/L H2SO4 and 0.05 mol/L H2SO4 + 0.02 mol/L NaCl solutions using electrochemical evaluation,SEM,EDS,and XPS.The results indicate that Cl-do not alter the semiconductor type of passive film on AlCoCrFeNi2.1 EHEA,but they considerably affect the compactness.Cl-change passive film properties by influencing the Al and Cr oxide contents;however,Ni is not affected by Cl-.The Ni-Al-rich phase is preferentially dissolved in 0.05 mol/L H2SO4 solution,and pitting corrosion and selective dissolution occur in 0.05 mol/L H2SO4 +0.02 mol/L NaCl solution.
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