Alloys superconducting

Cryogenic -273 to -20°C Copper alloys Austenitic (stainless) steels Aluminium alloys Superconduction Rocket casings, pipework, etc. Liquid O2 or N2 equipment... 

E. W. Collings, A Source book of titanium alloy superconductivity, Plenum Press, New... 

In conclusion, recent investigations of the 123 Ca overdoping reveal a much more complex picture consisting of alloying superconducting 123 with a non-superconducting substance (Ca-123 molecules with localized Ca-induced hole carriers) supporting once more physical phase separation. 

If cooled to near absolute zero, all metals become superconducting. Several metals and alloys superconduct even at marginally higher temperatures of 10-15 K. To maintain a superconductor at these extremely low temperatures requires liquid helium (bp, 4 K) as a coolant. 

Alone among all known physical phenomena, the transition in low-temperature (T < 25 K) superconducting materials (mainly metals and alloys) retains its classical behaviour right up to the critical point thus the exponents are the analytic ones. Unlike the situation in other systems, such superconducting interactions are tndy long range and thus... 

It is widely used as filaments for mass spectrographs and ion gauges. Rhenium-molybdenum alloys are superconductive at 10 K. 

The metal has unusual superconductive properties. As little as 1 percent gadolinium improves the workability and resistance of iron, chromium, and related alloys to high temperatures and oxidation. 

Rhenium hexafluoride is a cosdy (ca 3000/kg) material and is often used as a small percentage composite with tungsten or molybdenum. The addition of rhenium to tungsten metal improves the ductility and high temperature properties of metal films or parts (11). Tungsten—rhenium alloys produced by CVD processes exhibit higher superconducting transition temperatures than those alloys produced by arc-melt processes (12). 

In the area of superconductivity, tetravalent thorium is used to replace trivalent lanthanides in n-ty e doped superconductors, R2 Th Cu0 g, where R = Pr, Nd, or Sm, producing a higher T superconductor. Thorium also forms alloys with a wide variety of metals. In particular, thorium is used in magnesium alloys to extend the temperature range over which stmctural properties are exhibited that are useful for the aircraft industry. More detailed discussions on thorium alloys are available (8,19). 

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... 

Titanium alloyed with niobium exhibits superconductivity, and a lack of electrical resistance below 10 K. Composition ranges from 25 to 50 wt % Ti. These alloys are P-phase alloys having superconducting transitional temperatures at ca 10 K. Thek use is of interest for power generation, propulsion devices, fusion research, and electronic devices (52). 

In addition, the copper industry s market development activities have resulted in appHcations such as clad ship hulls, sheathing for offshore platforms, automotive electrical systems including electric vehicles, improved automobde radiators, solar energy, fire sprinkler systems, parts for fusion reactors, semiconductor lead frames, shape memory alloys, and superconducting ceramics (qv) containing copper oxides. 

Other specialized uses of Sn and its alloys are as type metal, as the molten-metal bath in the manufacture of float glass and as the alloy NbsSn in superconducting magnets. The many industrial and domestic uses of tin compounds are discussed in later sections these compounds account for about 15% of the tin produced worldwide. 

H. Kammerling Onnes (Nobel Prize for Physics, 1913) discovered superconductivity in Leiden in 1911 when he cooled mercury to the temperature of liquid helium. Many other materials, mostly metals and alloys, were subsequently found to display superconductivity at very low temperatures. 

The generally accepted theory of electric superconductivity of metals is based upon an assumed interaction between the conduction electrons and phonons in the crystal.1-3 The resonating-valence-bond theory, which is a theoiy of the electronic structure of metals developed about 20 years ago,4-6 provides the basis for a detailed description of the electron-phonon interaction, in relation to the atomic numbers of elements and the composition of alloys, and leads, as described below, to the conclusion that there are two classes of superconductors, crest superconductors and trough superconductors. 

Fig. 3.—The curve represents the calculated values of the superconductivity critical temperature. The circles are the experimental values for the elements and for binary alloys between adjacent elements.

A listing of ternary, quaternary and higher order systems is found in Table 1. An extensive and more detailed compilation concerning the structural chemistry and phase equilibria in the low-T phase diagrams of the (Mre, MrExXM i, Mj )4B4 type is available , along with a discussion of the physical properties and low-T behavior of these alloys (i.e., superconductivity and magnetism) - " . 

Superconductivity has been known since 1911, and superconducting systems based on various metal alloys (e.g., NbTi and Nb3Sn) are currently used as magnets and in electronics. These materials exhibit superconductivity only at temperatures below 23 K and require cooling by liquid helium. The discovery of ceramics that exhibit superconductivity at temperatures up to 120 K, the so-called high-temperature superconductors, has sparked a tremendous amount of scientific activity and commercial interest around the world. 

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