Fig. 2 demonstrates that the surface of the sample contains,
in addition to chromium oxides, iron (ca. 10 at.%),
nickel (ca. 3 at.%) and silicon inclusions (up to 2 at.%). The
analysis shows that the above elements do not participate in
the composition of the oxide film and are probably present in
the crevices where part of the underlying steel surface is exposed
to XPS analysis. Since XPS is an integral method and
collects information from a large surface area, the spectrum
contains signals of both, the oxide layer and the crevices.