Observation of REBCO delamination in the resistive insulation nested coils

Fuente: arXiv
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Autori principali: Lu, Jun, Dixon, Iain, Kim, Kwangmin, Xin, Yan, Bai, Hongyu
Natura: Preprint
Pubblicazione: 2025
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author Lu, Jun
Dixon, Iain
Kim, Kwangmin
Xin, Yan
Bai, Hongyu
author_facet Lu, Jun
Dixon, Iain
Kim, Kwangmin
Xin, Yan
Bai, Hongyu
contents The REBCO coated conductor has the potential to be widely used in ultrahigh field magnets. It is well known, however, that it is not mechanically strong against delamination in the direction normal to its surface due to its intrinsic layered structure. Therefore, conductor delamination is one of the major design challenges for REBCO magnet coils. As a part of the development of the 40 T all-superconducting magnet at the National High Magnetic Field Laboratory, USA (NHMFL), a dry-wound resistive-insulation-nested-coils (RINC) was designed to reach 25.8 T. It used surface-treated stainless-steel tape as a co-wind to control the turn-to-turn contact resistance, and was fabricated and tested in a liquid helium bath. During the test, two of the double pancake modules exhibited resistive transitions at a current significantly lower than the designed value. The postmortem inspection of the REBCO conductor of these modules by reel-to-reel magnetization at 77 K found sections of very low critical current. Further investigations of one section by chemical etching, visual inspection, and electron microscopy revealed that conductor of this section was delaminated. We present the detailed findings of these postmortem characterizations. The implication of this type of delamination for future magnet designs will be discussed.
format Preprint
id arxiv_https___arxiv_org_abs_2512_16647
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Observation of REBCO delamination in the resistive insulation nested coils
Lu, Jun
Dixon, Iain
Kim, Kwangmin
Xin, Yan
Bai, Hongyu
Superconductivity
The REBCO coated conductor has the potential to be widely used in ultrahigh field magnets. It is well known, however, that it is not mechanically strong against delamination in the direction normal to its surface due to its intrinsic layered structure. Therefore, conductor delamination is one of the major design challenges for REBCO magnet coils. As a part of the development of the 40 T all-superconducting magnet at the National High Magnetic Field Laboratory, USA (NHMFL), a dry-wound resistive-insulation-nested-coils (RINC) was designed to reach 25.8 T. It used surface-treated stainless-steel tape as a co-wind to control the turn-to-turn contact resistance, and was fabricated and tested in a liquid helium bath. During the test, two of the double pancake modules exhibited resistive transitions at a current significantly lower than the designed value. The postmortem inspection of the REBCO conductor of these modules by reel-to-reel magnetization at 77 K found sections of very low critical current. Further investigations of one section by chemical etching, visual inspection, and electron microscopy revealed that conductor of this section was delaminated. We present the detailed findings of these postmortem characterizations. The implication of this type of delamination for future magnet designs will be discussed.
title Observation of REBCO delamination in the resistive insulation nested coils
topic Superconductivity
url https://arxiv.org/abs/2512.16647