TEM and AES investigations of the natural surface nano‐oxide layer of an AISI 316L stainless steel microfibre

Summary The chemical composition, nanostructure and electronic structure of nanosized oxide scales naturally formed on the surface of AISI 316L stainless steel microfibres used for strengthening of composite materials have been characterised using a combination of scanning and transmission electron microscopy with energy‐dispersive X‐ray, electron energy loss and Auger spectroscopy. The analysis reveals the presence of three sublayers within the total surface oxide scale of 5.0–6.7 nm thick: an outer oxide layer rich in a mixture of FeO.Fe 2 O 3 , an intermediate layer rich in Cr 2 O 3 with a mixture of FeO.Fe 2 O 3 and an inner oxide layer rich in nickel.