High-Temperature Oxidation of Fe-Cr Base Alloys with Particular Reference to Fe-Cr-Y Alloys

Abstract

The oxidation kinetics of iron‐chromium alloys containing 25 and 37.5% chromium and small additions of yttrium and various other rare earth metals have been measured between 700° and 1200°C. Agreement with the parabolic rate law is generally observed for all alloys. Iron‐chromium binary alloys have good oxidation resistance, but lose their protective oxide film due to spalling above 1000°C. Alloys containing yttrium, lanthanum, dysprosium, gadolinium, and erbium exhibit both good oxidation resistance and scale retention. Enhanced scale retention for alloys containing yttrium and the rare earth metals is attributed to the formation of internal as well as external oxide.