Investigation of structure and composition of surface oxides in a high chromium martensitic steel

An investigation has been carried out on the composition and thickness of the oxide films formed on the high chromium martensitic steel MANET under various oxidation conditions (ambient, 600°C in air and in hydrogen). X-ray diffraction methods were combined with ion beam techniques (Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA)) to study the oxide films. In all cases the oxide layers were found to be highly enriched with Mn, a minor alloying component in the original steel. No evidence of the formation of pure Cr 2O 3 was found even in the samples oxidised under a low oxygen potential.