Reel-to-Reel Selective Electroplating of Cu Stabilizer for Multifilamentary Coated Conductors

A continuous, reel-to-reel DC electroplating process has been developed to produce high-quality Cu stabilizer for multifilamentary coated conductors. Due to the large resistivity difference between the silver-coated superconducting filaments and the insulating oxidized grooves between the filaments, selective electroplating was achieved on laser-striated multifilamentary tapes. Every superconducting filament in the tape was homogeneously copper-coated without continuous deposition of copper on the insulating grooves. The multifilamentary tapes are then fully stabilized without significant reduction in critical current and the benefit from filamentization on AC loss is maintained. The high flexibility of electroplating enabled us to produce multifilamentary coated conductors with copper stabilizer thickness from 5 to 30 μm. A 10-m tape was fabricated to demonstrate the scalability of fully-stabilized, low-loss multifilamentary coated conductors. The stabilized 12-filamentary CC tape is able to achieve four-fold AC loss reduction with minimal reduction in its critical current.