Preparation of Au nano-tips for in-situ investigation of early-age localized corrosion of three metals by scanning electrochemical microscope

Abstract

In this work, scanning electrochemical microscopy (SECM) was employed for corrosion studies of carbon steel, stainless steel and aluminum alloy in a neutral chloride solution. The SECM Au tips at nano-scale size were prepared by laser-assisted pulling method and characterized by scanning electron microscope (SEM) and electrochemical method. In the SECM test, the I-/I3- redox couple was used as a mediator for mapping the temporal and spatial evolutions of tip current on each metallic substrate with or without a scratched nanocomposite coating. The results reveal that it is appropriate to combine the generation-collection (G-C) mode of SECM with the feedback current mode in order to elucidate the possible reaction mechanism and pathways underlying the localized corrosion of the three metals investigated.