Abstract: A series of nano-iron oxides with different particle sizes or bulk phases were firstly prepared from cheap inorganic iron salts by precipitation or sol-gel methods. Then, the nano-iron nitride samples were prepared from the as-synthesized nano-iron oxides by temperature-programmed reaction(TPR) method under ammonia atmosphere. The characterizations of X-ray diffraction and transmission electron microscope demonstrate that nano-iron nitride can be produced from the nano-iron oxides by TPR method. There are apparent differences in the particle sizes of iron nitride prepared from different precursors. Within some range of sizes, smaller iron oxide precursor leads to larger iron nitride particles. For the γ phase and α phase iron oxides with similar particle sizes, the former is more likely to agglomerate during the nitridation. The iron nitride particles retain the morphology of the oxide precursors.

Key words: Precipitation method, Sol-gel method, Temperature-programmed reaction method, Nano-iron oxide, Nano-iron nitride