Application of Electrochemical Atomic Force Microscopy (EC-AFM) in the Corrosion Study of Metallic Materials

Abstract

Electrochemical atomic force microscopy (EC-AFM), a branch of a scanning probe microscopy (SPM), can image substrate topography with high resolution. Since its inception, it was extended to a wide range of research areas through continuous improvement. The presence of an electrolytic cell and a potentiostat makes it possible to observe the topographical changes of the sample surface in real time. EC-AFM is used in in situ corrosion research because the samples are not required to be electrically conductive. It is widely used in passive film properties, surface dissolution, early-stage corrosion initiation, inhibitor efficiency, and many other branches of corrosion science. This review provides the research progress of EC-AFM and summarizes the extensive applications and investigations using EC-AFM in corrosion science.

Characterizing Batteries by In Situ Electrochemical Atomic Force Microscopy: A Critical Review

“…Furthermore, the sample under evaluation must be electrically connected to allow a potential to be applied and coupled with a reference and counter electrode (or single counter‐reference), forming the electrochemical cell that is the key defining feature of EC‐AFM (Figure 1b). [ 36 ] As the AFM probe is usually submerged in the liquid electrolyte within an open cell while scanning (with a cover surround to prevent electrolyte evaporation), the laser must be focused onto the cantilever via an optical window, meaning angle compensation must be applied to mitigate refraction between the gas/solid/liquid interfaces. For all‐solid‐state batteries no liquid cell is needed but the scanning probe is configured to image a cross‐section of the battery, or the electrode (electrolyte free) or electrolyte surface.…”

In Situ Analytical Techniques for the Investigation of Material Stability and Interface Dynamics in Electrocatalytic and Photoelectrochemical Applications

“…[168] This EC-AFM technique has been used extensively to observe changes in surface roughness during the corrosion of metals. [169][170][171][172][173][174] However, biasing an insulated conductive probe with only the tip exposed as a second independent working electrode in a four-electrode system enables SECM via the AFM tip. [175] This four-electrode EC-AFM can map the local electrochemical activity or potential at the electrode surface along with the topography at sub-100 nm resolution.…”

Advances in Atomic Force Microscopy: Imaging of Two- and Three-Dimensional Interfacial Water

“…For example, EC-AFM has limited scanning rate, thus some fast interface reactions cannot be monitored in real time. In addition, drift during scanning make it difficult to obtain reliable surface characteristics ( Chen et al, 2020 ). These limitations are expected to be overcome in the near future by developing low-noise cantilever deflection sensor ( Fukuma et al, 2005 ) and drift-compensated data acquisition schemes ( Abe et al, 2007 ).…”