Ribbon superconductors

Ribbon superconductor with coating from niobium nitride

Niobium nitride is corresponded to the best superconductive compounds (i_c=10 MA/cm²), but it is applied in film coating on small substrates only for manufacturing physical apparatus. A new prospective usage of niobium nitride is manufacturing ribbon superconductors on its basis. The main disadvantage of niobium nitride (its fragility) overpasses in a ribbon cable.

We designed the technology and equipment for ion-plasma coatication of superconductive coating from niobium nitride on a copper ribbon. Ribbon superconductor is stabilized and suits for manufacturing of industrial magnet bobbins after length increase.

Niobium nitride is synthesized at magnetron dispersion of niobium in the mixture of argon and nitrogen. For improving of technical parameters of ribbon superconductor the intermediate layers from titanium and titanium nitride are drawn between bearing basis from copper and coating from niobium nitride. Original magnetron highly productive pulverizeres provide high critical characteristics of the ribbon superconductor.

The vacuum magnetron facility for receiving of ribbon superconductor samples on the basis of niobium nitride has been designed and manufactured (fig. 9). Manufactured samples (fig. 10) have the following parameters:

Fig.9 Magnetron facility for ribbon superconductor forming

Continued investigations of superconductive coatings for ribbon superconductors

Superconductive intermetallic compounds of niobium

Superconductive intermetallides of niobium Nb₃Sn and Nb₃Al have high values of critical parameters. One of compounds - Nb₃Sn - is applied at manufactured of wire cables using processes of plastic and thermal processing of half-finished products. We replaced laborious method of plastic processing of wire by more operative one - forming of ribbon superconductors by magnetron precipitation.

There have been received samples of superconductive coatings Nb₃Al and Nb₃Sn on bearing basis from copper ribbon in the laboratory of IPT INP. Sample length is 60 cm, width - 6 cm. The coating in 1 mkm thickness are drawn at homogeneous magnetron dispersion of niobium and the second component. Crystal lattices of synthesized compounds relate to corresponding structural type with tabular parameter values.

At present time the preparation to cryogen experiments goes to the end and after their termination the critical parameters of ribbon superconductors will be defined. On the final stage of technology elaboration the sample tests of superconductive cables are planned, which are of interest of industrial magnet manufacturing.

High-temperature superconductors

There have been obtained coating samples from high-temperature ceramics Y-Ba-Cu-O on substratum from polycrystalline oxides in the laboratory of IPT INP. The coating is synthesised at magnetron dispersion of target of stochiometric compound in argon and oxide mixture. The coating from compound Y-Ba-Cu-O has a stochiometric solution, corresponding type of crystallite structure and high-temperature superconductivity.
The elaboration of methods of coating forming on metallic bearer is planned.