XAFS analysis of corroded metal surfaces with molten salts by conversion-electron-yield method

Abstract

We have measured XAFS spectra of metal surfaces corroded with melting salt (NaCl, KCl, and Na2SO4). Steel samples used were S45C, SCM435, SUS310S, and SUS304. We measured the Fe K-edge XAFS spectra for all samples and the Ni K-edge for SUS310S and SUS304 samples before and after the corrosion. The XANES spectra of samples before the corrosion show metallic structure because surface oxide thickness is thinner than probing depth with a conversion yield XAFS method. Each result of these XAFS spectra gives good agreements with the FEFF calculation in the assumption of bcc and/or fcc structure. The Fe K-edge spectra of steel samples except SUS310S after corroded treatment show existence bonding between Fe and another light element although the spectra of SUS310S samples before and after corroded treatment are much the same.