1985 Volume 93 Issue 1084 Pages 750-756
A NbN powder has been prepared from NbCl5 and a stoichiometric amount of a reducing metal at the temperature ranging 200°C to 1100°C in a nitrogen stream (150-200ml/min). The influences of Al, Zn and Mg metals on nitridation of NbCl5 were examined. In the NbCl5-Al-N2 system, NbN was formed above 500°C. After heating the powder mixture at 1100°C for 1h, the N/Nb ratio in the product was 0.88. The ratio was slightly higher than the theoretical value. On the other hand, in the NbCl5-Zn-N2 system, formation of NbZn3 alloy was observed from 400°C to 500°C, and NbN was formed above 700°C. After heating the powder mixture at 900°C for 1h, the N/Nb ratio in the product was 0.63, but the N/Nb ratio decreased above 900°C. In the NbCl5-Mg-N2 system, NbN was formed above 500°C, and MgO formed from oxygen, which was present in trace amounts, was removed by washing the product with 1N HCl solution. The particle size of NbN powder ranged from 0.1 to 0.3μm. After heating the powder mixture at 1100°C for 1h, the N/Nb ratio in the product was 0.91. When heated at 1100°C for 4h, the N/Nb ratio in the product was 0.94, which was the highest value among the three reducing agents. The above results indicated that Mg was the most effective reducing agent.
