The oxidation of steels is critically influenced by its constituent alloying elements. These alter the classical three-phase model of the external oxide scales and in addition can introduce internal oxidised regions. This paper considers the oxidation of a number of nickel containing Fe based alloys of varying compositions, including stainless steel. These have been oxidised under different conditions to produce a number of scale morphologies, which have been characterised using two SEM based techniques; Electron Backscatter Diffraction (EBSD) and Energy Dispersive x-ray Spectroscopy (EDS). Results have shown that nickel promotes the formation of a fibrous internal scale, consisting of iron oxide particles (or iron/chromium oxide in the case of stainless steel) along grain boundary regions. Nickel is rejected from these oxide particles and consequently nickel content is enriched in neighbouring metallic areas.