Iron oxides, are typical products of iron (steel) oxidation at high temperatures. Type of atmosphere, presence of alloying elements and chemical surface pretreatment influence the phase composition and microstructure of the formed surface layers. The investigation of iron (steel) at high temperatures is important from both academic and technological points of view. This study can provide information on how oxidation occurs on the surface and what iron (steel) can be expected in the behaviour of this material in real applications under similar conditions. The layers of iron (steel) oxide on the surface are not easy to analyze because of their complex phase composition, not stoichiometry and/or very fine particles.This book has been translated with Artificial Intelligence.