| The reaction precess and the morphology of vanadium powders obtained from a vapor phase reaction of VCl₄ and NH₃at 200-1400℃, under a pressure of an atmosphere and 4.9 KPa were determined. The vapor phase reaction products and thermally decomposed powders obtained at various temperatures ware investigated by means of X-ray diffraction, TGA, SEM and TEM. Three types of VN were obtained in the vapor phase reaction depending on the temperature amorphous VN at 250℃ 8F-type VN crystals at 500℃ and a mixture of nitrogen-richer VN and 8F-type crystals above 1050℃. The size of the reaction products obtained at 1400℃ was less than 0.04㎛ and about 0.08-0.16㎛ for the vapor phase reaction and the thermal decomposition in NH₃flow system, respectively. The atomic ratio, N/V, decreased with the increase of the reaction temperature and the lattice parameter calculated for various reaction products obtained at different temperatures above 800℃ were almost constant. |
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