摘要 : Local Electrochemical Impedance Mapping (LEIM) methodology was adopted to quantify the propagation of electrochemically active regions with a micrometric precision. The method consisted in the use of the gradient modulus of the ad... 展开 Local Electrochemical Impedance Mapping (LEIM) methodology was adopted to quantify the propagation of electrochemically active regions with a micrometric precision. The method consisted in the use of the gradient modulus of the admittance map as a parameter for the spatial quantification. Numerical simulations were used to optimize the experimental conditions, namely the AC frequency, the distance between the local bi-probe and the working electrode, and the distances between the probes for the local bi-probe used for the local current mapping. This analysis was reinforced by experimental verifications on coated electrodes. The quantitative LEIM methodology was successfully applied to follow the delamination kinetics on Zn coated with the polyvinyl butyral polymer in NaCl solutions. At 1 kHz, the LEIM response only reflected the position of the anodic front beneath the polymer because oxygen reduction reaction was diffusion limited and hence, independent of the applied potential. This novel LEIM methodology completes the set of usual tools used to investigate the delamination mechanisms on metal substrates. (C) 2017 Elsevier Ltd. All rights reserved. 收起