共晶高熵合金AlCoCrFeNi_(2.1)在H_(2)SO_(4)溶液中的腐蚀行为

Corrosion Behavior of AlCoCrFeNi_(2.1)Eutectic High-Entropy Alloy in Sulfuric Acid Solution

利用电化学测试、SEM、EDS、XPS等方法研究了AlCoCrFeNi_(2.1)共晶高熵合金(EHEA)在0.05 mol/L H_(2)SO_(4)溶液与0.05 mol/L H_(2)SO_(4)+0.02 mol/L NaCl溶液中的腐蚀行为。结果表明,AlCoCrFeNi_(2.1)EHEA在H_(2)SO_(4)溶液中的钝化行为与局部腐蚀受Cl-影响明显;Cl-不改变AlCoCrFeNi_(2.1)EHEA钝化膜的半导体类型,但对钝化膜的致密性影响明显;钝化膜中的Ni受Cl-影响较小,Cl-主要通过影响Al、Cr氧化物的含量进而改变钝化膜的性质;在0.05 mol/L H_(2)SO_(4)溶液中,AlCoCrFeNi_(2.1)EHEA的腐蚀为富Ni-Al相选择性溶解;在0.05 mol/L H_(2)SO_(4)+0.02 mol/L NaCl溶液中,则为点蚀与选择性溶解。

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-CoCrFeNi_(2.1),consists of both fcc and bcc microstructure,imparting excellent mechanical properties.The recent research on AlCoCrFeNi_(2.1)EHEA primarily focuses on its mechanical properties.However,corrosion resistance of AlCoCrFeNi_(2.1)EHEA is rarely discussed,which is crucial for the application of new materials.This work investigates the corrosion behavior of AlCoCrFeNi_(2.1)EHEA in 0.05 mol/L H_(2)SO_(4)and 0.05 mol/L H_(2)SO_(4)+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 AlCoCrFeNi_(2.1)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 H_(2)SO_(4)solution,and pitting corrosion and selective dissolution occur in 0.05 mol/L H_(2)SO_(4)+0.02 mol/L NaCl solution.