In Situ Investigation of Localized Corrosion of Aluminum Alloys in Chloride Solution Using Integrated EC-AFM/SECM Techniques

Abstract

Scanning electrochemical microscopy ͑SECM͒ has been integrated with electrochemical atomic force microscopy ͑EC-AFM͒, and applied for in situ studies of localized corrosion of Al alloys in NaCl solution. The instrument utilizes a dual mode probe, which functions both as a normal cantilever and as an ultramicroelectrode. The I − /I 3 − redox mediator was used for mapping of local electrochemical current. Concurrent topography and electrochemical activity maps have been obtained on the same surface area with micrometer lateral resolution. Preliminary results show ongoing localized dissolution related to intermetallic particles in the Al alloys, which may occur well below the breakdown potential.

In situ scanning electrochemical probe microscopy for energy applications

“…Combined -SECM-AFM (atomic force microscopy) [33][34][35][36] is one of the most documented hybrid SECM modes. By integrating a micro/nanoelectrode in an AFM probe, the surface topography can be tracked accurately with AFM, while the electrochemical properties of a substrate can be measured using SECM.…”

Methods of photoelectrode characterization with high spatial and temporal resolution

“…When the desired UME tip/substrate separation distance is comparable to the roughness of the sample surface, several advanced versions of SECM may be employed, including scanning-force microscopy, 64 hybrid SECM/atomic-force microscopy (AFM), 65,66 intermittent-contact SECM, [61][62][63] and electron transfer/ion transfer SECM. 67 Although this section has focused on the implementation of SECM for the analysis of the spatial variation of product formation on photoelectrode surfaces, SECM can also be used to investigate local changes in pH 68 and corrosion processes, [69][70][71][72][73][74] analyze surface coverage of adsorbed intermediates (surface interrogation SECM), [75][76][77][78][79] and measure short-lived intermediates. 54,80 When used in conjunction with SPCM, SECM also offers an interesting possibility to semi-quantitatively measure the local Faradaic efficiency of photoelectrodes.…”

Investigation of Localized Catalytic and Electrocatalytic Processes and Corrosion Reactions with Scanning Electrochemical Microscopy (SECM)

“…It complements other scanning probe techniques such as the scanning reference electrode technique (SRET) [178,179], conductive scanning force microcopy (CSFM), electrochemical scanning tunneling microscopy (ECSTM), and scanning Kelvin probe techniques which are popular methods for the investigation of functional materials [180]. Basic experimental approaches include the imaging of the permeability of applied protective coatings [181][182][183][184][185][186][187][188][189][190][191][192][193], the imaging of regions with distinctly higher electron transfer rates which may be precursor sites for pitting corrosion [29,57,[194][195][196][197][198][199][200][201][202][203][204][205][206][207], the initiation of pitting corrosion by local generation of aggressive species at the UME [208,209] and the detection of active corrosion by collecting released species [55,58,60,104,[210][211][212][213][214]…”