Niobium-titanium superconductors

Hoc85] Hochstuhl, P, Lattice Instability and Metastable Phases in Niobium-Titanium Superconductors, KfK Report No. 3931 (in German), Kemfor-scbungszentrum Karlsruhe, West Germany, July 1985... 

Special Alloys. AHoys of tin with the rater metals, such as niobium, titanium, and 2kconium, have been developed. The single-phase alloy Nb Sn [12035-04-0] has the highest transition temperature of any known superconductor (18 K) and appears to keep its superconductivity in magnetic... 

But even the magic of superconductors has its limits. Magnet designs involve relatively sharp bends in the conductor, a requirement which has led to difficulties with such materials as niobium-tin, a great superconductor but brittle compared to niobium-titanium. Cooling the conventional superconductors to extremely low temperatures is also a problem. And there is the propensity of the superconductors to lose their superconductivity—to go normal— in the presence of strong magnetic fields. 

The alloy niobium titanium (NbTi) and the intermetallic compound of niobium and tin (Nb3Sn) are the most technologically advanced low-temperature superconductors presently available. Even though NbTi has a lower critical field and critical current density, it is often favored because of... 

Niobium is important as an alloy addition in steels (see Steel). This use consumes over 90% of the niobium produced. Niobium is also vital as an alloying element in superalloys for aircraft turbine engines. Other uses, mainly in aerospace appHcations, take advantage of its heat resistance when alloyed singly or with groups of elements such as titanium, tirconium, hafnium, or tungsten. Niobium alloyed with titanium or with tin is also important in the superconductor industry (see High temperature alloys Refractories). 

Crucibles of titanium nitride and zirconium nitride are utilized for the melting of lanthanum alloys. ZrN, HfN and TaN are also used as electrodes in electronic valves. Niobium and zirconium nitrides could be used as superconductors due to their relatively high superconductor transition temperatures of 16.8 and 10 K respectively. 

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