Iron – Molybdenum – Oxygen

Pierre Perrot

Introduction

The Fe-Mo-O system presents an interest because it appears in the preparation of ferromolybdenum alloys by metallothermic reduction of MoO₂. Some Fe-Mo oxides have also important industrial applications by forming a protective coating over molybdenum steels. On an another hand, the molybdate Fe₂(MoO₄)₃ is the active component in Fe-Mo based oxidation catalysts. Iron and molybdenum oxides are “easily reduced” oxides, which means that equilibria between solid phases are easily obtained under H₂-H₂O or CO-CO₂ atmospheres. Such atmospheres give access not only to the phase compositions, but to the oxygen potential at equilibrium with an accuracy better than that obtained from electromotive force measurements. The main experimental investigations on...