Auger electron spectroscopy analysis of chromium depletion in a model Ni–16Cr–9Fe alloy oxidized at 950 °C

A complete chromium depletion profile with its depth resolution in the nanometre range was obtained on a Ni–16Cr–9Fe model alloy after a 10 h oxidation at 950 °C in air. Auger electron spectroscopy coupled to ion sputtering and energy-dispersive X-ray spectroscopy were used to measure the chromium depletion profile. The chromium content at the oxide/alloy interface is below 0.5 wt.%. This exceptionally low Cr content is in agreement with Wagner’s model for binary alloys.