Ammonium dicyanamide as a precursor for the synthesis of metal nitride and carbide nanoparticles

We designed a highly efficient, fast and facile route for the syntheses of both metal nitrides and carbides starting from an organic reagent ammonium dicyanamide and the corresponding metal oxides, respectively. Four technologically important metal nitrides and four carbides including cubic VN, CrN, NbC, TaC, hexagonal GaN, AIN, WC, MoC were synthesized successfully at moderate temperatures. It is interesting to find that ammonium dicyanamide is not only a highly efficient nitridation reagent but also a highly efficient carburization reagent. The metal oxides are completely converted into the corresponding metal nitride and carbide nanoparticles at relatively low temperatures. A possible mechanism is proposed to explain the results of the reactions between the organic reagent and metal oxides. It is found that highly active carbon nitride materials condensed by ammonium dicyanamide play the crucial roles in the reduction, nitridation and carburization processes. This novel route may provide new insights into the synthesis of other metal nitrides and carbides. (c) 2007 Elsevier B.V All rights reserved.