Performance of Polyvinyl Formal Insulated Cu-Nb/Nb3Sn Wires for React-and-Wind Process

Masahiro Sugimoto, Hirokazu Tsubouchi, Kota Katayama, Hideki Ii, Daisuke Asami, Satoshi Awaji, Hidetoshi Oguro

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


In this study, polyvinyl formal (PVF) insulated Cu-Nb/Nb3Sn wires were successfully developed for react-and-wind (R&W) process. The bronze-processed Nb3Sn wires, composed of the Nb-rod-method Cu-Nb reinforcing stabilizer around the Nb3Sn filament bundle, have superior mechanical strength against tensile and bending stress, not only at low temperature but also at room temperature. The Cu-Nb/Nb3Sn wires of 0.8- or 1.3-mm bare-diameter were heat-treated at 670 °C for 96 h on the stainless bobbins of predetermined diameter. Then, prebending strains were applied to the reacted wires under individual conditions. After that, the PVF insulation was applied with a thickness of 20 or 40 μm. Enhancement of the critical currents occurred by applying the appropriate prebending treatments and controlling the strain under PVF insulation processing to ±0.5% or less. This paper presents the performance of the PVF-insulated Cu-Nb/Nb3Sn wires applicable to R&W coils.

Original languageEnglish
Article number6001205
JournalIEEE Transactions on Applied Superconductivity
Issue number5
Publication statusPublished - 2019 Aug


  • CuNb/NbSn wire
  • Nb-rod-method CuNb
  • polyvinyl formal insulation
  • pre-bending effect
  • react-and-wind


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