Saeedikhani Mohsen, Vafakhah Sareh, Blackwood Daniel J
Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576, Singapore.
School of Chemical and Biomolecular Engineering, The University of Sydney, Darlington, NSW 2006, Australia.
Materials (Basel). 2022 May 24;15(11):3764. doi: 10.3390/ma15113764.
In this paper, the finite element method was used to simulate the response of the scanning vibrating electrode technique (SVET) across an iron-zinc cut-edge sample in order to provide a deeper understanding of the localized corrosion rates measured using SVET. It was found that, if the diffusion layer was neglected, the simulated current density using the Laplace equation fitted the experimental SVET current density perfectly. However, the electrolyte was not perturbed by a vibrating SVET probe in the field, so a diffusion layer existed. Therefore, the SVET current densities obtained from the local conductivity of the electrolyte would likely be more representative of the true corrosion rates than the SVET current densities obtained from the bulk conductivity. To help overcome this difference between natural conditions and those imposed by the SVET experiment, a local electrolyte corrected conductivity SVET (LECC-SVET) current density was introduced, which was obtained by replacing the bulk electrolyte conductivity measured experimentally by the local electrolyte conductivity simulated using the Nernst-Einstein equation. Although the LECC-SVET current density did not fit the experimental SVET current density as perfectly as that obtained from the Laplace equation, it likely represents current densities closer to the true, unperturbed corrosion conditions than the SVET data from the bulk conductivity.
在本文中，采用有限元方法模拟扫描振动电极技术（SVET）在铁 - 锌切割边缘样品上的响应，以便更深入地理解使用SVET测量的局部腐蚀速率。研究发现，如果忽略扩散层，使用拉普拉斯方程模拟的电流密度与实验测得的SVET电流密度完美拟合。然而，在实际情况中，振动的SVET探针并不会扰动电解质，因此存在扩散层。所以，从电解质局部电导率获得的SVET电流密度可能比从整体电导率获得的SVET电流密度更能代表真实的腐蚀速率。为了帮助克服自然条件与SVET实验条件之间的这种差异，引入了局部电解质校正电导率的SVET（LECC - SVET）电流密度，它是通过用基于能斯特 - 爱因斯坦方程模拟的局部电解质电导率替代实验测量的整体电解质电导率而得到的。虽然LECC - SVET电流密度不像从拉普拉斯方程得到的那样与实验SVET电流密度完美拟合，但它可能比来自整体电导率的SVET数据更能代表接近真实、未受扰动的腐蚀条件下的电流密度。
