High-Efficient Copper Shunt Deposition Technology on REBCO Tape Surfaces

Abstract

For low-ohmic electrical applications of REBCO- coated conductors (CCs), a copper stabilizer with thickness of at least 20-30 μm is indispensable. The electroplating process investigated herein was developed in the last ten years. We investigated and proposed Cu pulse plating on a CC surface protecting the tape, preventing sharp edges and facilitate winding work. With an optimized chemistry of the copper sulfate CuSO 4 + H 2 SO 4 solution, we deposited a shiny, ductile, and nonporous copper layer. Due to cell-specific current load-controlled pulse plating technology, both Ni-based Hastelloy and NiW substrates could be plated with a current density of up to 200 mA/cm 2 . It reveals that pulse- controlled electrodeposition in a reel-to-reel technique brings the CC production to perfection. The nonvacuum copper plating technique is targeting a production speed of 100 m/h. The method meets the urgent need for simplified conductors and a reduced cost/performance ratio. We report about the electric and chemical parameters of a robust reel-to-reel facility. An improvement of the deposition rate and an increase of the Cu deposition speed up to 100 m/h is discussed.