Phase Detection Interferometric Microscopy of Electrode Surfaces. Measurement of Localized Dissolution of Iron Electrodes

摘要

Phase detection interferometric microscopy (PDIM) was used to obtain high resolution surface images of 100 micro m diameter iron disk exposed to 0.1M H2SO4. The initiation and growth of corrosion pits at short time (0-30 sec) were observed on relatively smooth regions of the Fe surface (r.m.s. surface roughness approx. 5.5 nm). The growth of pits at open circuit was measured with 1 nm resolution from the time of initiation to depths of 50 nm. The rate of vertical pit growth from PDIM analysis is characterized by the rate equation, y = 0.15 t2, where y is the pit depth (NM) and t is time (s). The topography of the Fe surface surrounding the pits remained virtually unchanged during pit growth, suggesting the presence of microscopic galvanic cells on the electrode surface. Mirroelectrode; High resolution imaging; Corrosion. (mjm)