High-Temperature Oxidation Study in a Multi-Oxidant Environment Using 18O Tracer

Abstract

The goal of this study was to use 18O-enriched water to better understand the role of H2O in high-temperature oxidation. Seven model and three commercial M-Cr and M-Cr-Al alloys were studied in air with 10% of H2O at 800 °C for 5 h. Oxygen from water vapor was more reactive than oxygen from the air and 18O enriched at the outermost layers of the formed Cr- and Al-rich oxides. Alloys with Al and/or Ti additions showed signs of internal oxidation but 18O was not enriched inside the alloy in locations with internal oxidation. Depending on the alloy Al content, the oxide went from Al oxidation beneath a chromia scale to external alumina scale formation.