摘要
以0.1 mol/L的Na2SO4为支持电解质,分别添加微量(1~10 mmol/L)的H+、Cl-、NO3-、NH3·H2O及其离子组合作为模拟常见大气污染物的腐蚀介质,研究7B50超高强度铝合金在腐蚀介质中的电化学腐蚀行为。采用循环极化曲线和电化学阻抗谱,得到不同腐蚀介质中的自腐蚀电位、自腐蚀电流密度、线性极化电阻、击穿电位、保护电位、点蚀转换电位及电荷转移电阻等参数,表征不同离子的侵蚀性能及其之间的相互作用。结果表明:微量的H+、Cl-、NH3·H2O使腐蚀速率增大数倍;1 mmol/L酸碱的侵蚀能力由大到小的顺序依次为NH3·H2O、H2SO4、HNO3、HCl;NO3-单独存在时具有缓蚀效应,与H+结合产生加速腐蚀的协同作用;Cl-存在下,电极的阳极极化程度最低,极化电流最大,局部腐蚀的发展程度也最大。
The corrosion behaviour of 7B50 aluminum alloy in simulative atmospheric pollutants solution was investigated using electrochemical methods. Ten different media were chosen based on common atmospheric pollutants, such as H+, Cl-, NO3- and NH3·H2O, or the combination of them. Parameters, such as corrosion potential, corrosion current density, linear polarization resistance, pitting potential, repassivation potential, pit transition potential, and charge transfer resistance are obtained from cyclic polarization curve and electrochemical impedance spectroscopy(EIS). The results show that H+, Cl-, NH3·H2O and OH- are all corrosive substances which increase the corrosion rate of 7B50 aluminum alloy several times, respectively, while NO3- is a corrosion inhibitor in spite of being more corrosive when integrated with H+. According to the electrochemical parameters, the corrosive ability of several acids and alkali(1 mmol/L) in decreasing order is NH3·H2O, H2SO4, HNO3, HCl. In addition, Cl- reveals the weakest anodic polarization of electrode when comparing with other ions, which means it has the highest anodic current density. Also, the localized corrosion of Cl- is the severest.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2015年第3期575-581,共7页
The Chinese Journal of Nonferrous Metals
基金
国家重点基础研究发展计划资助项目(2012CB619502
2010CB731701)
湖南省自然科学基金资助项目(12JJ6040)
国家自然科学基金资助项目(51201186)
国家重大科研仪器设备研制专项(51327902)
关键词
7B50铝合金
大气污染物
电化学腐蚀
循环极化曲线
电化学阻抗谱
7B50 aluminium alloy
atmospheric pollutant
electrochemical corrosion
cyclic polarization curve
electrochemical impedance spectroscopy
