Preparation of Zirconium Nitride Powder from Zirconium Chloride (IV)

Abstract

ZrN powder was prepared from ZrCl₄ by the halogenide process in a nitrogen gas flow (100-200ml/min) at the temperatures from 200°C to 1050°C. Particularly, the influences of reducing agents, Al, Mg and Zn powder were examined. The Al powder was found to be the most effective reducing agent among them, and ZrN powder was odtained above 800°C. In the slow nitriding reaction, however, an alloy phase of Al₃Zr was formed. The apparent activation energy of the reaction was 28.7kcal/mol (850°-1050°C). The fine powder (0.1-0.3μm) of one-phase ZrN was obtained at 1050°C after 1h. The lattice parameter a and the crystallite size of ZrN were 4.575Å and 259Å, respectively. However, because of the sublimation loss of ZrCl₄, the residual Al was found in the products. This Al was removed almost completely by washing with 1N NaOH. On the other hand, in the system ZrCl₄-Mg-N₂, the process of the nitriding reaction was slow, and only coarse particles of ZrN were obtained. In the system ZrCl₄-Zn-N₂, ZrN was not prepared.