Currentless Deposition of Nb₃Sn in Molten Salts

The production possibility of superconducting Nb₃Sn-coatings by currentless method in molten salts is investigated. In this connection interaction between niobium and KCl-NaCl (1:1 mol.)-SnCl₂ or (Cs-K-Na)Cl (eutectic.)-SnCl₂ melts and cathodic electroreduction of tin on niobium electrode at temperature 530-800°C are studied. According to the X-ray diffraction data, in the process of currentless holding of the niobium sample in tin-containing melts, multiphase coatings containing Nb₃Sn are formed as a rule. This corresponds to the data of currentless chronopotentiometry. The coatings obtained were found to be superconducting with maximum critical temperature T_c = 17,0 ÷ 17,8 K and critical current density j_c = 2 ÷ 3 × lO⁶ A/cm² in a transversal magnetic field B = 4 T.