Sumitomo Electric Industries, Ltd. (SEI) has been developing REBCO tape fabrication by Fluorine-free MOD (FF-MOD) method. The FF-MOD method is a promising technique for low cost REBCO fabrication since this method uses conventional coating technique, no special equipment such as vacuum chamber,easily prepared inexpensive solutions, and material yield achieve nearly 100%. Moreover, the FF-MOD method had been demonstrated a high growth rate of ~ 100 nm/sec in [1], [2]. For applications that require a large amount of tape, such as small fusion reactors, cost reduction is essential, and this is an issue that must be addressed if REBCO tape is to be used in actual demand and the market is to expand in the future. We believe that the FF-MOD method is the shortest way to overcome this challenge.
Until recently, it has been difficult to fabricate long tapes with artificial pinning centers dispersed in the film by the FF-MOD method, but we have succeeded in introducing BMO (M = Hf, Zr) nanoparticles made by a solvothermal method [3] into the film on Clad substrate by adding preformed-nanoparticles to the FF-MOD solution and developing long tapes over 100 m [4].In addition, we have demonstrated REBCO fabrication on IBAD-templated Hastelloy substrates, achieving the in-field critical current comparable to the Clad one.
[1] Y. Ishiwata et al., IEEE Trans. Appl. Supercond., 23 (2013) 7500804.
[2] L. Soler et al., Nat. Commun., 11 (2020) 334.
[3] N. Chamorro et al., RSC Adv., 10 (2020) 28872.
[4] T. Yoshihara et al., IEEE Trans. Appl. Supercond., 33(2023) 6600205.
A part of this work was performed at High Field Laboratory for Superconducting Materials (HFLSM) under the GIMRT Program of Institute for Materials Research (IMR), Tohoku University (Proposal No.: 202112-HMKGE-0403).