Cu含量对铁基中熵合金耐腐蚀及抗菌性能的影响

Effect of Cu Content on Corrosion Resistance and Antibac-terial Properties of Iron-Based Medium Entropy Alloy

摘要:

采用水冷铜坩埚磁悬浮真空熔炼炉制备了(Fe_63.3Mn₁₄Si_9.1Cr_9.8C_3.8)_99.5?xCu_xAg_0.5 (x=1，2，3，4，5，at%)合金，并对合金试样进行抗菌时效处理，研究Cu含量对合金耐腐蚀性能以及抗菌性能的影响。结果表明，经过固溶时效处理后的中熵合金均为fcc结构，随着Cu含量的提高，fcc1富铁基体上逐渐析出了富Cu和富Ag的fcc2相。合金在3.5%（质量分数）NaCl溶液中的耐腐蚀性能优于AISI304。随Cu含量的增加，腐蚀电流密度先减小而后增加，容抗弧半径先增大后减小，表明合金的耐腐蚀性能先增强后减弱。合金在大肠杆菌悬浮液中的腐蚀速率呈现出先增大后减小的趋势，x=2合金的耐生物腐蚀能力最优，而抗菌性能和腐蚀性能存在倒置关系。富Cu和富Ag的fcc2相能有效提升合金的抗菌性能，x=5合金的抗菌性能最优，抗菌率达到99.94%.

Abstract:

(Fe_63.3Mn₁₄Si_9.1Cr_9.8C_3.8)_99.5?xCu_xAg_0.5 (x=1, 2, 3, 4, 5, at%) alloys were prepared by water-cooled copper crucible magnetic levitation vacuum melting furnace. The effects of Cu contents on microstructure, corrosion resistance, and antibacterial performance of the alloys were investigated. The results show that the medium entropy alloys possess fcc phase after solid solution and aging treatment. With the increase in Cu content, the Cu-enriched and Ag-enriched fcc2 phase is precipitated on the fcc1 Fe-rich matrix. The corrosion resistance of the alloys in 3.5wt% NaCl solution is superior to that of AISI304. The corrosion current density first decreases and then increases, and the impedance arc radius first increases and then decreases, indicating an initial enhancement and subsequent weakening of the corrosion resistance as the Cu content increases. Moreover, the corrosion rate of the alloys in Escherichia coli suspension shows a trend of increasing first and then decreasing. When x=2 the alloy exhibits the best corrosion resistance, and there is a trade-off effect between the corrosion resistance and antibacterial performance. The fcc2 phase effectively enhances the antibacterial performance of the alloy, and the alloy of x=5 shows the optimal antibacterial rate of 99.94%.