dark gray; fcc, a=0.4388nm; hardness, 8+ Mohs; electrical resistivity 78μοhm· cm; transition temp 15.2K; can be prepared by heating Nb metal in excess N2 or NH3 to 700°C–1100°C; used in the form of 99.5% pure sputtering target for increasing electrical stability of diodes, transistors, and integrated circuits [KIR81] [CIC73] [CER91]
Dark gray crystals. Transition
temperature 15.2 K. Insoluble in
HCL, HNO3 and H2SO4; but attacked by hot caustic, lime, or
strong alkalis evolving NH3.
Niobium nitride (NbN) thin films were noticed at an early stage because of their critical transition temperatures as low as 16-17K which could find wide applications in superconducting microelectronics. Because of its complicated phase diagram, NbN is difficult to prepare in the pure face-centered cubic, rocksalt structure.
Niobium nitride is used as superconductor. Used in absorbinganti-reflective coatings. It used to produce arc-welding rods and in steel.
1. Taking metallic niobium and nitrogen as raw materials, the crushed metallic niobium is sent into the nitriding furnace, and then nitrogen or ammonia is introduced to make it react at 700-1100 to directly synthesize niobium nitride. Or in the crushed metal niobium powder add charcoal powder, so that it is fully mixed and sent to the reduction furnace, and then pass into the hydrogen and nitrogen, at a temperature of 1250 reduction reaction 2h to get niobium chloride.
2.Direct method Prepare niobium nitride from metallic niobium and nitrogen, the reaction formula is as follows: NB2O5+2N+5C==2NbN+5CO.
The crushed metallic niobium is fed into the nitriding furnace, and nitrogen or ammonia gas is introduced to make it react at 700-1100C for 1-2h, which is obtained as niobium nitride.
3. Reduction method In the presence of carbon, niobium nitride is prepared from niobium pentoxide and nitrogen with the following reaction formula: Nb+N==NbN.
In the crushed metal niobium powder add charcoal powder, so that it is fully mixed and sent to the reduction furnace, and then through the hydrogen and nitrogen, at a temperature of 1250 in the reduction reaction of 2h to get niobium nitride.
