Niobium

Niobium Facts

Niobium, also known as columbium, is number 41 on the periodic table. With a melting point of 2468°C, it qualifies as a refractory metal. Niobium has a density of 8.57 gm/cc. It has many properties that make it an excellent candidate for fabricated parts that must be made of a refractory metal. Niobium offers good ductility and weldability under a clean, dry, inert gas or a vacuum.

Technical Information

Niobium is a rare, soft, malleable, ductile, gray-white metal. It has a body-centered cubic crystalline structure and in its physical and chemical properties it resembles tantalum.

Atomic Weight: 92.9064
Density: 8.57 g/CC
Melting Point: 2750 K, 2468°C, 4490°F
Boiling Point: 5017 K, 4927°C, 8571°F
Coefficient of Thermal Expansion: (20°C) 7.1 x 10-6/°C
Electrical Resistivity: (20°C) 15 microhms-cm
Electrical Conductivity: 13.2% IACS
Specific Heat: .126 cal/g/°C
Thermal Conductivity: .523 cal/cm2/cm°C/sec
Crystal Structure: bcc
Thermal Neutron Cross Section: 1.1 b

The corrosion resistance of niobium is more limited than tantalum and this must be taken into consideration. The limitation stems from its sensitivity to most alkalis and certain strong oxidants.

However, niobium is totally resistant to such highly corrosive media as wet or dry chlorine, bromine, saturated brines, ferric chloride, hydrogen sulfide, and sulfur dioxide as well as nitric and chromic acids. It is also resistant to sulfuric and hydrochloric acids within specific temperature and concentration limits.

Niobium is also resistant to attack by many liquid metals such as: Li <1000°C, Na, K + NaK <1000°C, ThMg <850°C, U <1400°C, Zn <450°C, Pb <850°C, Bi <500°C and Hg <600°C.

Niobium has the ability to form stable, passive oxides and therefore, it can provide unique solutions to many corrosion problems. However, niobium cannot be used in air at temperatures exceeding 200°C. Refer to the table entitled Corrosion Resistance for additional information.

The cold working properties of niobium are excellent. Because of its bcc crystal structure, niobium is a very ductile metal that can undergo cold reductions of more than 95% without failure. The metal can be easily forged, rolled or swaged directly from ingot at room temperature.

Annealing is necessary after the cross-sectional area has been reduced by approximately 90%. Heat treating at 1200° C for one hour causes complete recrystallization of material cold worked over 50%. Note that the annealing process must be performed either in an inert gas or in a high vacuum at pressures below 1 X 10-4 Torr. Of the two methods, the use of a vacuum is preferred.

Niobium is well suited to deep drawing. The metal may be cupped and drawn to tube but special care must be taken with lubrication. Sheet metal can also easily be formed by general sheet metal working techniques. The low rate of work-hardening reduces springback and facilitates these operations.

Stock Supplies

These sizes are in stock, subject to prior sale. We also supply other sizes and alloys as well. See additional material information below.

sheet

  • .005″ x 12″ x Coil”
  • .010″ x 12″ x Coil”
  • .015″ x 12″ x Coil”
  • .020″ x 12″ x Coil”
  • .036″ x 12″ x Coil”
  • .040″ x 11.5″ x R/L
  • .060″ x 12″ x R/L
  • .125″ x 12″ x R/L
  • .250″ x 12″ x R/L
  • .375″ x 12″ x R/L
  • .500″ x 12″ x R/L

plate

  • .250″ x 12″ x R/L
  • .375″ x 12″ x R/L
  • .500″ x 12″ x R/L

wire

  • .005″ Dia x 100 ft
  • .010″ Dia x 100 ft
  • .015″ Dia x 100 ft
  • .020″ Dia x 100 ft
  • .025″ Dia x 100 ft
  • .030″ Dia x 100 ft
  • .040″ Dia x 100 ft
  • .050″ Dia x 100 ft
  • .060″ Dia x 100 ft
  • .080″ Dia x R/L Coil
  • .090″ Dia x R/L Coil
  • .125″ Dia x R/L Coil

rod

  • .125″ Dia x R/L
  • .156″ Dia x R/L
  • .187″ Dia x R/L
  • .250″ Dia x R/L
  • .312″ Dia x R/L
  • .375″ Dia x R/L
  • .500″ Dia x R/L
  • .625″ Dia x R/L
  • .750″ Dia x R/L
  • .875″ Dia x R/L
  • 1.000″ Dia x R/L
  • 1.250″ Dia x R/L
  • 1.500″ Dia x R/L

tubing

  • .125″ OD x .015″ wall x R/L
  • .187″ OD x .020″ wall x R/L
  • .250″ OD x .020″ wall x R/L
  • .312″ OD x .020″ wall x R/L
  • .375″ OD x .020″ wall x R/L
  • .500″ OD x .020″ wall x R/L
  • .625″ OD x .020″ wall x R/L
  • .750″ OD x .020″ wall x R/L
  • .875″ OD x .020″ wall x R/L

Material Information

  • ASTM B393 Type R04210 (Sheet, Plate)
  • ASTM B392 Type R04210 (Wire, Rod)
  • ASTM Certifications upon request
  • No cutting fee for custom lengths
  • Custom Sizes Available
  • Custom Stocking Plans Available

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