铸态和烧结态AlCoCrFeNi高熵合金模拟海水腐蚀性能研究

(西安工业大学 材料与化工学院,西安 710021

真空电弧熔炼; 放电等离子烧结; 高熵合金; 模拟海水; 电化学腐蚀

Study of Simulated Seawater Corrosion Performance of AlCoCrFeNi High Entropy Alloy in As-Cast and Sintered State
XIONG Yanjie,XU Dapeng,CHENG Zhaohui,WEI Jingpeng

(School of Materials and Chemical Engineering,Xi'an Technological University,Xi'an 710021,China)

vacuum arc melting; spark plasma sintering; high entropy alloy; simulated seawater; electrochemical corrosion

DOI: 10.16185/j.jxatu.edu.cn.2020.01.011 http://xb.xatu.edu.cn

备注

为了研究铸态和烧结态AlCoCrFeNi高熵合金在模拟海水介质下的电化学腐蚀性能,采用真空电弧熔炼和放电等离子烧结工艺制备AlCoCrFeNi高熵合金,分别采用X射线衍射仪(XRD)和光学显微镜(OM)分析其相结构和微观组织,采用电化学工作站对其进行电化学试验测试。研究结果表明: AlCoCrFeNi铸态合金组织呈现等轴晶形貌,物相为单一BCC结构; 烧结态合金组织呈球形形貌,在900 ℃的烧结温度下,除了BCC相,还出现极少量的B2相以及FCC相。烧结态和铸态自腐蚀电位分别为-0.535 4 V和-0.667 6 V,自腐蚀电流密度分别为2.914 9×10-5 A·cm-2和2.150 4×10-5 A·cm-2,铸态合金的钝化区比烧结态宽。2种合金均只出现一个容抗弧,且铸态合金的容抗弧半径远大于烧结态合金,表明铸态合金的耐蚀性优于当前烧结温度下的烧结态合金。

In order to study the electrochemical corrosion performance of as-cast and sintered AlCoCrFeNi high-entropy alloys in simulated seawater medium,vacuum arc melting and spark plasma sintering processes were used to prepare AlCoCrFeNi high-entropy alloys.Their structure and microstructure were analyzed in the XRD and OM,respectively,and the electrochemical test was performed in the electrochemical workstation.The results show that the AlCoCrFeNi as-cast alloy has an equiaxed morphology and its phase shows a single BCC structure; the sintered alloy has a spherical morphology.At 900 ℃ sintering temperature,a small amount of B2 and FCC phase as well as BCC phase appear.The sintered and cast self-corrosion potentials are -0.535 4 V and -0.667 6 V,respectively,and their self-corrosion current density are 2.914 9×10-5 A·cm-2 and 2.150 4×10-5 A·cm-2.The passivation zone of the as-cast alloy is wider than that of the sintered alloy.Both alloys have only one capacitive arc,and the radius of the capacitive arc of the as-cast alloy is much larger than that of the sintered alloy,which indicates that the corrosion resistance of the as-cast alloy is better than the sintered alloy at the current sintering temperature.