Fabrication of long lengths of YBCO coated conductors using a continuous reel-to-reel dip-coating unit

A low-cost, non-vacuum, solution precursor route has been developed to produce epitaxial Gd₂O₃ and Eu₂O₃ buffer layers and YBa₂Cu₃O_7-δ (YBCO) superconductors on biaxially textured metal substrates. On sol-gel Eu₂O₃ seed layers with sputtered YSZ and CeO₂ top layers, YBCO film with a J_c of over 1 MA/cm² at 77 K was obtained. On all solution buffer layers (CeO₂/Eu₂O₃/Ni), YBCO film with a J_c of 200,000 A/cm² at 77 K was grown using pulsed laser deposition (PLD). Meter lengths of epitaxial and crack-free Gd₂O₃ buffer layers were fabricated on cube textured Ni-W (3 at.%) substrates for the first time. High quality YBCO films were deposited on Rolling-Assisted Biaxially Textured Substrates (RABiTS) using a trifluoroacetate (TFA) precursor approach. The precursors were either spin-coated or dip-coated and decomposed in a newly developed fast 3-hour burn-out step followed by post-annealing. In a stationary burn-out route, we have produced 40 cm long crack-free YBCO TFA precursors on RABiTS. On short segments, YBCO films with a J_c of over 500,000 A/cm² at 77 K were grown on all PLD buffered-Ni substrates (CeO₂/YSZ/CeO₂/Ni).