Depth Elemental Imaging during Corrosion of Hot-Dip Galvanized Steel Sheet by Confocal Micro XRF Analysis

Abstract

The elucidation of the mechanism for steel corrosion under a coating layer has been attracting research attention. Herein, we utilized a confocal micro-X-ray fluorescence (XRF) analytical instrument to conduct non-destructive elemental analysis near the surface of a steel sheet. Using this method, elemental map images of steel sheet cross sections were obtained without sample destruction. To confirm corrosion suppression in the presence of Mg ions, we observed the corrosion behavior of hot-dip galvanized steel sheets immersed in an aqueous NaCl solution to which Mg ions were added. By using the confocal micro XRF system, the elution of the coating components and the precipitation process of the corrosion products were confirmed.

In situ observation of electrochemical reaction of Zn primer steel plate in NaCl solution using confocal micro‐x‐ray fluorescence imaging

“…The CM‐XRF technique has been applied to observe chemical reactions in solutions 17–23 . Chemical reactions such as corrosion and deposition occur on the surface of solid samples in solution.…”

“…The CM-XRF technique has been applied to observe chemical reactions in solutions. [17][18][19][20][21][22][23] Chemical reactions such as corrosion and deposition occur on the surface of solid samples in solution. In these reactions, the corroded metals migrated to the solution, which can be monitored using a CM-XRF.…”

X-ray Fluorescence Spectrometry

“…7 The publication of the ISO standard 20289 for the TXRF spectrometry analysis of water, particularly drinking and ground water, represented a major advance in using of the technique. 8 As complex and heterogeneous systems, a corrosion behavior of hot-dip galvanized steel sheets immersed in an aqueous NaCl solution was observed by a confocal micro-XRF instrument developed by Akioka et al 9 The confocal 3D-XRF system combining two polycapillary lenses in a vacuum provided crosssectional elemental maps without sample destruction. This analytical method is an effective means of elucidating the corrosion mechanism at the solid-liquid interface between a Zn coating layer and its base steal substrate.…”