In the present work the oxidation behavior of ageing treated steel was examined up to 1000°C in different environments (O2 and CO2) and with different heating rates. The examination was conducted by means of thermogravimetric analysis, scanning electron
microscopy and X-ray diffraction. In this study it was deduced that in the case of O2 an oxide scale is formed on top of the steel. The oxidation is uniform and the growth of the scale is more intent at low
heating rate. It consist of different Fe, Mn, Mo and Cr oxides which are adjusted in the form of layers. This phenomenon was
explained by the different diffusion coefficients of each metal in the already formed scale. Regarding the oxidation in CO2, the scale formation takes place at a lower temperature than in the case of O2. Hence the examined substrate is more vulnerable in CO2.