Corrosion, the spontaneous dissolution of metal in a galvanic cell, is an age-old problem that continues to have a large economic impact. The fundamental processes governing the kinetics and mechanism of initiation of corrosion remains poorly understood. One challenge in studying corrosion initiation is that corrosion occurs stochastically and heterogeneously at different sites on metals.
To tackle this problem, we will use correlative microscopic methods, including a nanoscopic scanning electrochemical probe (e.g., SECCM, as shown in Figure 1), to study the local electrochemistry at individual corrosion sites. We will experimentally measure the structure-dependent thermodynamics, the kinetics of metal dissolution reaction. Our single-site study will bridge the dimension between experiment and theoretical computational modeling, shedding new light on the dynamics of corrosion initiation.
SECCM allows the mapping of local activity of metal dissolution kinetics. Colocalized mapping using atomic force microsscopy (AFM) and electron backscatter diffraction (EBSD) will provide information about the topography of the pit formed after the local dissolution, as well as the local crystal orientation of the sample. Correlative maps of this kind provide multi-dimensional data that allow unabmious activtity measuremnt at the strucutre of interest, e.g., grain boudnaries.