text: Mechanically, NbSn is extremely brittle and thus cannot be easily drawn into a wire, which is necessary for winding superconducting magnets. To overcome this, wire manufacturers typically draw down composite wires containing ductile precursors.  The "internal tin" process includes separate alloys of Nb, Cu and Sn.  The "bronze" process contains Nb in a copper–tin bronze matrix.  With both processes the strand is typically drawn to final size and coiled into a solenoid or cable before heat treatment. It is only during heat treatment that the Sn reacts with the Nb to form the brittle, superconducting niobium–tin compound. The powder-in-tube process is also used.
  The high field section of modern NMR magnets are composed of niobium–tin wire.