利用干涉仪研究磁场对铁磁性金属点蚀的影响

Research on Effect of Magnetic Field on Pitting Corrosion of Ferromagnetic Metals with Interferometer

利用马赫-曾德尔干涉仪研究了磁场对铁磁性金属局部腐蚀过程的影响。结合传统电化学方法和动电位极化测量研究了纯铁电极在0.1mol/L氯化钠溶液中局部腐蚀的情况,先利用CCD采集电极/溶液界面处干涉条纹视频图像,随后采用傅里叶变换和自适应带通滤波器分析干涉条纹,最后通过干涉条纹动态相位重建再现电极/溶液界面局部腐蚀动态过程。结果表明,没加磁场时,电极/溶液界面的中间区域会先出现局部溶解现象,但随着电位的增大,电极/溶液界面局部腐蚀程度加深,最后整个电极/溶液界面达到活化溶解。在外加磁场条件下,电极表面的腐蚀程度与磁感应强度正相关,呈现出明显的边缘腐蚀现象。即外加磁场能够加剧铁磁性金属的电化学腐蚀。

A Mach-Zehnder interferometer is employed to study the effect of magnetic field on the local corrosion process of a ferromagnetic metal. The local corrosion of a pure iron electrode in the 0.1 mol/L NaC1 solution is investigated with the combination of traditional electrochemical method and potentiodynamic polarization measurement. The video images of interference fringes in the electrode^solution interface are first recorded by CCD, then these fringes are analyzed by Fourier transform and the adaptive bandpass filter, and finally the dynamic process of local corrosion in the electrode/solution interface is reproduced by the dynamic phase reconstruction of interference fringes. The results show that, without the external magnetic field, the local corrosion appears only in the middle area of the electrode/solution interface at first, but the local corrosion area of the electrode/solution interface soon expands with the increase of voltage, and finally the entire electrode/solution interface is activated and dissolved. With the external magnetic field, the corrosion degree of the electrode surface is positively correlated with the magnetic induction, and an obvious edge corrosion phenomenon occurs. In other words, the external magnetic field can accelerate the electrochemical corrosion of ferromagnetic metals.