Ammonium dicyanamide as a precursor for the synthesis of BN, NbN, Mo₂N and WN nanoparticles

In this paper, we designed a facile solid-state reaction method by selecting an organic reagent ammonium dicyanamide and metal oxides as precursors to prepare four important metal nitrides including BN, NbN, WN and Mo₂N in sealed ampoules. The experimental results indicate that the metal oxides are completely converted into the corresponding nitrides. These nitrides are composed of finely divided nanoparticles with rather small and uniform size. In particular, NbN, Mo₂N and WN have the size of 5, 4 and 5 nm with fairly narrow size distribution. It is found that ammonium dicyanamide is a highly efficient nitridation reagent and exhibits some interesting condensation processes. A possible mechanism is proposed and investigated.