Iron - Manganese - Oxygen

Pierre Perrot

Introduction

The Fe-Mn-O system has raised very soon a huge interest because manganese is a useful element generally found in iron ores. Mn has a beneficial effect on the plasticity of steels, decreases the stacking fault energy, increases the nitrogen solubility and gives a shape memory effect. Mn being easily oxidized gives non metallic inclusions in iron [1981Mik] and their conditions of formation have ben well explored. [1929Sch] showed that MnO has for effect to stabilize iron oxides, thus making harder their reduction by CO. The first FeO-MnO tentative diagram, found in [1930Ben] presents a miscibility gap in the solid state which is considered as doubtful by the author and has not been confirmed since, although [1943Whi, 1964Lev] reproduce it in their reviews. [1937Wen] presents a Fe-FeO-MnO phase diagram accepted today, phas...