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Nanometer Resolved Real Time Visualization of Acidification and Material Breakdown in Confinement
Author(s) -
Merola Claudia,
Cheng HsiuWei,
Dworschak Dominik,
Ku ChingShun,
Chiang ChingYu,
Renner Frank Uwe,
Valtiner Markus
Publication year - 2019
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.201802069
Subject(s) - materials science , corrosion , crevice corrosion , x ray photoelectron spectroscopy , electron backscatter diffraction , scanning electron microscope , alloy , diffraction , nanometre , nanoscopic scale , metallurgy , composite material , chemical engineering , optics , nanotechnology , microstructure , physics , engineering
Localized surface reactions in confinement are inherently difficult to visualize in real‐time. Herein multiple‐beam‐interferometry (MBI) is extended as a real‐time monitoring tool for corrosion of nanometer confined bulk metallic surfaces. The capabilities of MBI are demonstrated, and the initial crevice corrosion mechanism on confined nickel and a Ni 75 Cr 16 Fe 9 model material is compared. The initiation of crevice corrosion is visualized in real time during linear sweep polarization in a 1 × 10 −3 m NaCl solution. Pre‐ and post‐experiment analysis is performed to complementarily characterize the degraded area with atomic force microscopy (AFM), optical microscopy, nano‐Laue diffraction (nano‐LD), scanning electron microscopy (SEM)/electron backscatter diffraction (EBSD), and X‐ray photoelectron spectroscopy (XPS). Overall, Ni 75 Cr 16 Fe 9 displays a better corrosion resistance; however, MBI imaging reveals 200 nm deep severe localized corrosion of the alloy in the crevice opening. Chromium rich passive films formed on the alloy contribute to accelerated corrosion of the confined alloy by a strongly acidifying dissolution of the passive film in the crevice opening. Nano‐LD further reveals preferential crystallographic defect and corrosion migration planes during corrosion. MBI provides nanometer accurate characterization of topologies and degradation in confined spaces. The technique enables the understanding of the initial crevice corrosion mechanism and testing modeling approaches and machine‐learning algorithms.