Electrochemical and thermal synthesis of Nb3Sn coatings on Nb substrates

•This study investigates the Electrochemical and Thermal Synthesis (ETS) of Nb3Sn films.•The Nb3Sn films were obtained by electrochemically deposited bronze layer on Nb substrates.•The 700 °C annealing allows the fabrication of Nb3Sn thin films on copper substrate.•The Nb3Sn films have good quality and have great potential for SRF application.•This study is a new route towards copper-based TFSRF cavities.