Observation of passive films on Fe-20Cr-xNi (x=0, 10, 20 wt.%) alloys using TEM and Cs-corrected STEM-EELS

Abstract

The structure and composition of passive film formed on Fe-20Cr-xNi (x = 0, 10, 20 wt.%) alloys in deaerated pH 8.5 borate buffer solution was examined by transmission electron microscope and Cs-corrected scanning transmission electron microscope-electron energy loss spectroscopy. Thickness of the passive film on each alloy was measured to be 2.5-2.7 nm and the passive film was enriched with Cr. The passive film formed on the alloys exhibited an amorphous structure, as confirmed by the lack of diffraction contrast and by the fast Fourier transform images taken within a region of the passive film on each alloy.