Improving the Thermal Conductivity of Niobium in Nb3Sn/Nb/Cu Structures by Solid-State Refining

Abstract

Experimental data are presented which demonstrate that the thermal conductivity of Nb in Nb3Sn/Nb/Cu structures can be raised by solid-state refining in the range 1200–1500 K, using titanium and zirconium electrolytic coatings, plates, or powders as impurity sinks. The removal of oxygen from the Nb layer increases its thermal conductivity by a factor of 3–4, without impairing the performance parameters of the superconducting Nb3Sn layer.