Preparation of Superconducting Tapes via a Continuous Electrochemical Process

Our recent advancements about a continuous process for the production of electrochemical deposited Y₁Ba₂Cu ₃O_7-delta (Y-123) films are presented. The process consists of alternate elemental deposition steps and thermal treatments. By unreeling through sequential modular sections, several tens meter long tapes are processed in a continuous way yielding the final coated superconductor (Y-123/Ag), suitable for industrial applications. The Y-123 phase constituting elements (Cu, Y, and Ba) are sequentially electrodeposited on both sides of an untextured 50 mum-thick silver tape. Following copper and Yttrium hydroxide deposition steps, an intermediate annealing transforms the precursors into a mixture of CuO and Y₂Cu₂O₅. After Barium hydroxide electroplating, a final thermal treatment in pure flowing oxygen allows the formation of the Y-123 superconducting phase. A strict control on deposit stoichiometry and thermal parameters seems to be crucial in order to achieve a good microstructure and high performances. To date the process allows to deposit on both sides of the substrate 0.5 mum-thick Y-123 films that exhibit critical current densities in excess of 20 kA/cm² (77 K, self-field), the highest reported value for this material obtained via an electrochemical process on untextured metal tape