CHARACTERIZATION OF NANOCRYSTALLINE TANTALUM NITRIDE FORMED BY SOLID-GAS REACTION DURING MECHANICAL ALLOYING

Tantalum nitride formed by solid-gas reaction of tantalum with molecul ar nitrogen driven by mechanical alloying has been examined by X-ray d iffraction and transmission electron microscopy. The experimental resu lts reveal that Ta2N with nanometric structure with grain size of 5-20 nm is produced by milling tantalum powders in nitrogen atmosphere. Tr ace Ta3N5 is also detected by electron diffraction pattern. The format ion of tantalum nitrides is believed to be associated with the chemiso rption of nitrogen onto clean metal surfaces created by milling. The d efects generated by mechanical alloying may have also an effect on sol id-gas reaction. (C) 1998 Elsevier Science S.A.