Nb47Ti

Nb47Ti, also written Nb-47Ti, is an alloy of niobium and titanium containing about 47 atomic percent titanium and 53 atomic percent niobium. It forms a ductile solid solution that becomes superconducting at cryogenic temperatures, making it a standard material for practical magnet technology.

Superconductivity in NbTi appears below a critical temperature of about 9.2 kelvin. The alloy also exhibits a high upper critical field in practical applications, allowing magnetic operation at several teslas. In engineering use, NbTi is typically stabilized by copper to provide electrical and thermal stability, and it is commonly processed into thin multifilamentary wires or cables.

Manufacturing designs for NbTi magnets usually involve wires where NbTi filaments are embedded in a copper or copper-alloy matrix (CuNbTi). The wires are drawn into thin strands and wound into magnet coils. This configuration, together with cryogenic cooling (often liquid helium), enables stable superconducting performance in large-scale magnets such as those found in research facilities and medical devices.

Applications and limitations: NbTi is widely used in superconducting magnets for particle accelerators, fusion devices, and magnetic resonance imaging (MRI) systems due to its good ductility, processing ease, and adequate performance at moderate fields. It is generally favored for fields up to around 8–10 teslas at liquid helium temperatures. For higher-field applications, alternative materials such as Nb3Sn or high-temperature superconductors are considered, reflecting the lower upper critical field and transition temperature of NbTi.