In this study, we investigated the preparation conditions of titanium nitride (TiN) through nitridation of nanosized titanium dioxide (TiO 2) without particle agglomeration. Synthesis of nanocrystalline TiN powder was attempted via ammonia (NH 3) nitridation of nanocrystalline TiO 2 powder. The nitridation behavior was investigated using thermogravimetry (TG) in an NH 3 atmosphere. Non-isothermal TG experiments showed that nitridation of the nanocrystalline TiO 2 powder began at ³750°C. Two types of experiments were performed using isothermal TG. In the first experiment, an argon atmosphere was used while heating at 5°C/min. On reaching the holding temperature (900 or 1,000°C), the atmosphere was changed to NH 3 /Ar (50/50 kPa). This atmosphere was used throughout the second experiment. The first experiment produced a nitride powder with severely agglomerated particles. In the second experiment, nano-sized powder particles with inhibited agglomeration were obtained, and long holding time of 6 h at 900 or 1,000°C was effective in obtaining the small nitrided particles.

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Gallium Nitride nano-particles (GaN NPs) are synthesized by a simple nitridation method. A mixture of commercially available ¢-Gallium Oxide (¢-Ga 2 O 3) and GaN powders with about 5¯m particle size was heated at temperatures ranging from 7001,000°C in an ammonia (NH 3) atmosphere for 1 h. In the powder mixture, the ¢-Ga 2 O 3 particles converted to GaN NPs agglomerates, while the GaN particles are slightly grown. When the mixture was heated in the NH 3 atmosphere at 900°C, GaN NPs varying from 30 to 50 nm and microsized GaN particles were obtained.