Niobium Bar
Niobium Metals, plate, bar, wire, tube, target
Purity 99.95% min.
Density 8.6 g/cc
SGS certificate
Niobium belongs to the group of refractory metals. Refractory metals are metals that have a higher melting point than platinum (1 772 °C). In refractory metals, the energy binding the individual atoms together is particularly high. Refractory metals have a high melting pointcoupled with a low vapor pressure, high modulus of elasticity and high thermal stability. Refractory metals are also characterized by a low coefficient of thermal expansion. Compared to other refractory metals, niobium has a relatively low density of only 8.6 g/cm3
Niobium is located in the same period as Molybdenum in the periodic table. Its density and melting point are therefore comparable to those of molybdenum. In the same way as Tantalum, niobium is prone to hydrogen embrittlement. The heat treatment of niobium therefore takes place in a high vacuum and not in a hydrogen atmosphere. Both niobium and tantalum also offer a high level of resistance against all acids and good formability.
At -263.95 °C, niobium has the highest transition temperature of all elements. Below this temperature, niobium is superconducting. And what is more, niobium boasts a very special range of properties:
| Properties | ||
| Atomic number | 41 | |
| Atomic mass | 92.91 | |
| Melting point | 2 468 °C / 2 741 K | |
| Boiling point | 4 900 °C / 5 173 K | |
| Atomic volume | 1.80 · 10-29 [m3] | |
| Vapor pressure | at 1 800 °C | 5 · 10-6 [Pa] |
| at 2 200 °C | 4 · 10-3 [Pa] | |
| Density at 20 °C | 8.55 [g/cm3] | |
| Crystal structure | body-centered cubic | |
| Lattice constant | 329.4 · 10-12 [m] | |
| Hardness at 20 °C | formed | 110 - 180 [HV10] |
| recrystallized | 60 - 110 [HV10] | |
| Modulus of elasticity at 20 °C | 104 [GPa] | |
| Poisson number | 0.35 | |
| Coefficient of linear thermal expansion at 20 °C | 7.1 · 10-6 [m/(m·K)] | |
| Thermal conductivity at 20 °C | 52 [W/(m·K)] | |
| Specific heat at 20 °C | 0.27 [J/(g·K)] | |
| Electrical conductivity at 20 °C | 7 · 10-6 [1/(Ω·m)] | |
| Specific electrical resistance at 20 °C | 0.14 [(Ω·mm2)/m] | |
| Sound speed at 20 °C | Longitudinal wave | 4 920 [m/s] |
| Transverse wave | 2 100 [m/s] | |
| Electron work function | 4.36 [eV] | |
| Capture cross-section for thermal neutrons | 1.15 · 10-28 [m2] | |
| Recrystallization temperature (annealing time:1 hour) | 850 - 1 300 [ °C] | |
| Superconductivity (transition temperature) | < -263.95 °C / < 9.2 K | |
