Niobium

Niobium Facts

In 1801 the chemist E. Hatchet examined a black mineral, which had been on display in the British Museum for over 150 years, only to discover that this black mineral contained iron and an unidentified substance of an acidic oxide nature. He named the new element columbium after the continent on which it was found.

Niobium is strongly associated with tantalum as they were discovered in the same mineral. In 1844 Heinrich Rose separated the two and introduced the name niobium after Niobe, the daughter of Tantalus. In the 1950’s Niobium was accepted as the official designation of element 41.

Pyrochlore is the most important niobium mineral and is basically titano-nobate, NaCaNb2O6F.

It is a shiny, silvery metal which is soft when pure. It resists corrosion due to an oxide layer on the surface. Nb is attacked by hot concentrated acids, but resists attack by alkalis even when they are molten.

The metal is prepared from Nb2O5 by reduction with carbon. It has a bcc structure. Niobium’s main application is as an alloying agent in steel. It is used in special steels and in welded joints (to increase strength) forming High Strength low Alloy steels.

It is quite ductile, capable of being rolled to sheet and bar. It can be welded using the inert gas shielded technique with copious gas flow before and after the weld on both sides.

It resists attack from almost all chemicals, but is in no way superior to tantalum. The ability to withstand oxidation especially at elevated temperatures makes niobium potentially useful for super alloys in gas turbine applications.

Atomic no.
Relative Atomic Mass
Melting Point
Boiling Point
Density
Electrical Resistivity
Young's Modulus
Heat Capacity
Abundance 
Thermal Conductivity
41
92.91
2477°C
4744°C
8570 kgm-3
150 nΩm
104.9 Gpa
24.6 J/K/mol
20 ppm
53.7 W/m/K 

The story of Nb production is a good example of the divergence between what I call the Galapagos islands metallurgy of the former Soviet Union versus the rest of the world.

 

While the rest of the world generally focused on the production of Ferro Niobium for special steels or Nickel-Niobium master alloy for super alloys, Soviet metallurgy mutated in another direction.  

 

Using Electron Beam technology the Soviet state fixated on the production of what was metallurgically purest not neccessarily on what was, by Western standards, most commercial.

 

There were three great centres of output in those days , Silmet in Estonia, Donetsk in Ukraine, and Ulba in Kazakhstan.  Each factory to a greater or lesser extent was then affected by the passing of the command system under which they received regular supply of raw material.

Although the system has now faded, the resurgence of demand for pure niobium for sputtering targets and other applications, means the vestiges survive. Silmet is now owned by Neo Materials and the skills have now found their lasting niche.

Lipmann Walton gained good experience of single, double or triple melted EB ingots in the old days, and it is the niche we still trade today as well as the scrap generated by end of life sputtering targets. 

© 2020 Lipmann Walton & Co. Ltd

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Niobium cut pieces