Niobium Carbonitrides

Crystal Structure of Niobium Carbide

Niobium carbide has a cubic-F lattice with a motif of Nb at 0,0,0, and carbon at 0,0,0.5. The carbide is not strictly stoichiometric but is represented here as such, with a lattice parameter of 4.4691 nm.

NbC_1
Crystal structure of NbC in perspective.
NbC_110
Projection of the crystal structure of NbC along a 110 direction.
NbC_111
Projection of the crystal structure of NbC along a 111 type direction.
NbC_cube
Projection of the crystal structure of NbC along a cube edge.

Publications

Niobium and Ferro-Niobium Production

Photographs courtesy of Dr Thomas Sourmail

The main production of niobium and an alloy or iron and niobium (ferroniobium) is at CBMM, Araxá, Brazil, where there are sufficient reserves to last for 500 years at current world consumption rates. The pyrochlore ore is mined simply by digging it out from open pits - at this stage it contains about 3% of Nb2O5. This is then enriched using the floatation process. The enriched ore is then reacted with aluminium to getter the oxygen and ferroniobium. Electron-beam refining is used to produce pure noibium. Most of the niobium produced is in the form of ferroniobium, which goes towards the production of huge quantities of microalloyed steels.

011
The open cast mine
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Floatation process ot enhance the niobium content of the ore
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Hot ferroniobium
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Ferroniobium
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Packing tin cans of ferroniobium
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Electron beam furnace for the refinement of niobium metal, producing 210 tonnes per annum
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Electron beam refined niobium ingot

Niobium carbide in Hardfacing Weld Deposit

The following micrographs are courtesy of Dr Mario C. Cordero-Cabrera.

167nbs
Fe-1.4C-6Cr-8Nb-1Si wt% hardfacing alloy. The white particles a niobium carbides (NbC) present in a matrix of retained austenite, martensite and some M_7C_3 particles.
167NbS-2
Fe-1.4C-6Cr-8Nb-1Si wt% hardfacing alloy. The white particles a niobium carbides (NbC) present in a matrix of retained austenite, martensite and some M_7C_3 particles.
168NbO
Fe-C-Nb-Si hardfacing alloy. The white particles a niobium carbides (NbC) present in a matrix of retained austenite, martensite, ferrite and some M_7C_3 particles.

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