Na对于Al早期大气腐蚀的影响  

Effect of Na on Early Atmospheric Corrosion of Al

作　　者：陈星晨 王杰[1] 陈德任 钟舜聪[1] 王向峰[1] CHEN Xingchen;WANG Jie;CHEN Deren;ZHONG Shuncong;WANG Xiangfeng(State Key L aboratory of Photocatalysis on Energy and Environment, School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350002, China)

机构地区：[1]福州大学机械工程与自动化学院能源与环境光催化国家重点实验室,福州350002

出　　处：《金属学报》2019年第4期529-536,共8页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目No.51675103;福州大学能源与环境光催化国家重点实验室基金项目No.SKLPEE-KF201719;福州科技局项目No.2018-G-35;Supported by National Natural Science Foundation of China(No.51675103);State Key Laboratory of Photocatalysis on Energy and Environment(No.SKLPEE-KF201719);Fuzhou Science and Technology Bureau(No.2018-G-35)

摘　　要：采用单脉冲激光诱导击穿光谱(LIBS)测量了大气环境中腐蚀35 d后金属Al的谱线,结合三维形貌测量,研究了Na元素在Al表面的深度分布。结果表明,Al表面的Na元素源于大气环境,且Na参与生成腐蚀产物NaAlCO_3(OH)_2,其含量随着腐蚀深度的增加呈幂函数衰减。不同腐蚀深度时NaAlCO_3(OH)_2的含量可以转变为阴极面积的变化,结合测量得到的Al的极化曲线,利用COMSOL软件建立了氧还原和阴极面积同时影响Al的大气腐蚀仿真模型,揭示Na对腐蚀机理的影响。计算结果表明腐蚀深度为6.155μm,与LIBS实验测得的Na元素深度一致。Aluminum and aluminum alloy are widely used in every field of modern life. It is especially important to understand the detailed mechanisms of aluminum atmospheric corrosion. Traditional studies only consider the role of oxygen reduction and focus on anions such as Cl-, SO42- in the environment, ignoring the effects of cations such as Na+ on the atmospheric corrosion. However, recent studies have shown that the effect of Na element on the corrosion of aluminum can not be ignored. In this work, singleshot laser-induced breakdown spectroscopy(LIBS) was used to measure the aluminum atomic lines after corrosion for 35 d in the atmospheric environment, and combined with a three-dimensional tomography measurement, to study the depth profiling of Na on the aluminum surface. The results show that the Na element on the surface of the aluminum originates from the atmospheric environment, and Na is involved in the formation of corrosion product NaAlCO3(OH)2. The content of NaAlCO3(OH)2 decreases as the depth increases following an exponential power function. The content decrease of NaAlCO3(OH)2 in different depths can be transformed into the change of cathode area. Combined with the measured polarization curve of aluminum, the atmospheric corrosion model of aluminum including the presence of oxygen reduction and the change of cathode area was established using COMSOL software. The calculated corrosion depth is 6.155 μm, which is consistent with the depth of Na element measured by LIBS experiments. By studying the distribution of Na cations and corrosion products, a simulation model was established to reveal the influence on corrosion mechanism, which is of great significance for the study of early atmospheric corrosion of aluminum.

关 键 词：大气腐蚀 激光诱导击穿光谱(LIBS) 三维形貌 腐蚀产物 COMSOL 

分 类 号：TG146[一般工业技术—材料科学与工程]