Use of Local Electrochemical Methods (SECM, EC-STM) and AFM to Differentiate Microstructural Effects (EBSD) on Very Pure Copper

Abstract

When aiming for an increased and more sustainable use of metals a thorough knowledge of the corrosion phenomenon as function of the local metal microstructure is of crucial importance. In this work, we summarize the information presented in our previous publications [1][2][3] and present an overview of the different local (electrochemical) techniques that have been proven to be effective in studying the relation between different microstructural variables and their different electrochemical behavior. Atomic force microscopy (AFM)[1], scanning electrochemical microscopy (SECM) [2], and electrochemical scanning tunneling microscopy (EC-STM) [3] were used in combination with electron backscatter diffraction (EBSD). Consequently, correlations could be identified between the grain orientation and grain boundary characteristics, on the one hand, and the electrochemical behavior on the other hand. The grain orientation itself has an influence on the corrosion, and the orientation of the neighboring grains also seems to play a decisive role in the dissolution rate. With respect to intergranular corrosion, only coherent twin boundaries seem to be resistant.

Investigating electrochemical corrosion at Mg alloy-steel joint interface using scanning electrochemical cell impedance microscopy (SECCIM)

“…Since the microelectrodes in SECM and SVET are usually used at a constant height (especially for imaging), they are not as sensitive to changes in the faradaic current at grain boundaries or microstructure 1 . While some improvements to SECM increases resolution enough to reveal grain boundaries 2 , 3 , it has limitations due to diffusional broadening when imaging because the microelectrode does not contact the specimen 4 . Newly developed microscopic, droplet-based corrosion measurement techniques such as scanning electrochemical cell microscopy (SECCM) are used to capture localized or confined region electrochemical responses that can perform high resolution probing of grain boundaries, defects, and microstructures 5 – 8 .…”

Localised aqueous corrosion of electroless nickel immersion gold-coated copper

“…Negative feedback indicates a less electrochemical active area while positive feedback indicates the opposite. The resulting local current map obtained while operating at the feedback mode provides insight into the spatially-resolved local electrochemical activity of the surface [31][32][33].…”