(1. 中南大学粉末冶金国家重点实验室，长沙 410083；
2. 中南大学材料科学与工程学院，长沙 410083)
摘 要: 采用静态失重法与电化学阻抗谱评价4种氨基酸对7B50超高强度铝合金在1 mol/L NaCl+0.1 mol/L HCl溶液中的缓蚀行为，并通过腐蚀形貌表征氨基酸的缓蚀机理。结果表明：氨基酸浓度越高、温度越低，氨基酸对铝合金的缓蚀效率就越高。添加氨基酸后，溶液中铝合金的表观活化能均增大，其中，半胱氨酸(Cys)和蛋氨酸(Met)的表观活化能最高，这归因于—SH或—SCH3基团对铝合金表面优良的吸附作用。在4种氨基酸中，0.05 mol/L半胱氨酸(Cys)中含—SH基团的缓蚀效率最高，室温下高达94.7%；Met的次之，主要是由于—SCH3的空间位阻效应所致；苯丙氨酸(Phe)的缓蚀性能较差；低浓度的组氨酸(His)缓蚀能力相对不佳，而高浓度的His在较高温下仍保持着较高的缓蚀效率，这说明His的缓蚀效率受温度的影响较小。因此，His相应的表观活化能也较低。浸泡实验后的金相结果表明：添加氨基酸后会不同程度地抑制铝合金的晶间腐蚀和点蚀。
关键字: 氨基酸；缓蚀剂；电化学阻抗谱；7B50铝合金
（1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The inhibition behavior of four amino acids for 7B50 aluminium alloy was investigated using the mass loss measurement and electrochemical impedance spectroscopy technique. The corrosion mechanism of amino acid was characterized by corrosion morphologies. The results show that the inhibition efficiency increases with the increase of concentration and the decrease of temperature. The apparent activation energies of aluminium alloys in the presence of amino acids are larger than that of the sample immersed in the blank solution. The apparent activation energies of cysteine(Cys) and methionine (Met) are highest due to the excellent adsorption ability of —SH or —SCH3 groups on the surface of aluminium alloy. The inhibition efficiency of 0.05 mol/L Cys at low temperature is best among these four studied amino acids, e.g., the inhibition efficiency of Cys is 94.7% at room temperature. Met is also S–containing amino acids, but its inhibition efficiency is lower than that of Cys due to the steric hindrance effect. In addition, relatively lower inhibition efficiency is achieved for phenylalanine (Phe). Histidine (His) with low concentration has very bad inhibition performance, however, at higher temperatures, relatively good corrosion inhibition capability of His with high concentration is shown up gradually. The effect of temperature on the inhibition efficiency of Histidine (His) is little. Consequently, the apparent activation energy of Histidine (His) is lower than other amino acids. The corrosion morphologies show that the intercrystalline corrosion and pitting corrosion of aluminium alloys are inhibited in the presence of amino acids.
Key words: amino acids; corrosion inhibitor; electrochemical impedance spectroscopy; 7B50 aluminium alloys
