Initial oxidation of Fe-Al and Fe-Cr-Al alloys: Cr as an alumina booster

TL;DR

This study investigates how chromium enhances the formation of protective alumina scales on Fe-Al alloys during initial oxidation, using surface chemistry analysis and confirming findings with ab initio calculations.

Contribution

It provides experimental evidence of Cr's role in boosting alumina scale growth and validates previous theoretical models.

Findings

Cr increases alumina scale formation on Fe-Al alloys.

Surface chemistry changes are detected from the first moments of oxidation.

Experimental results agree with ab initio calculations.

Abstract

The boosting effect of Cr on the growth of the protective alumina scale on Fe-Al alloys is investigated by x-ray photoelectron spectroscopy. Using low oxygen pressure the surface chemistry of the alloys is monitored starting from the first moments of oxidation. Chromium effect on the Fe-Al surface-bulk exchange is clearly detected by analyzing the measured surface concentrations within the atomic concentration models. Previous ab initio calculations agree well with the present experiments.