Electrochemical synthesis of Nb3Sn coatings on Cu substrates

This work aims at contributing to the development of superconducting Nb 3 Sn thin films for possible applications, as for instance in superconducting radio frequency (SRF) cavities. The synthesis of Nb–Sn coatings was carried out on copper substrates by electrodeposition from 1-butyl-3-methylimidazolium chloride (BMIC) ionic liquids containing SnCl 2 and NbCl 5 . Cyclic voltammetric curves were recorded to identify the reduction potentials of Nb and Sn ionic species. Electrodeposition was performed at 40 and 400 mA/cm 2 and 130 °C. The CV demonstrated that BMIC has a suitable potential window for co-deposition of Nb and Sn. The electrodeposited coatings showed a cubic Nb 3 Sn phase with (211) preferred orientation, a disordered orthorhombic NbSn 2 phase and Sn–Cu phases. Film thickness was from 200 to 750 nm. These results suggest that electrodeposition of Nb–Sn coatings on copper substrates could be a suitable route to one day replace the current expensive Nb SRF cavities.