Heating and loading process improvement for indium inserted mechanical lap joint of REBCO tapes

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14 Citations (Scopus)

Abstract

A mechanical lap joint of REBCO high-temperature superconducting (HTS) tapes with an indium foil inserted between joint surfaces has been proposed for segment-fabrication of HTS magnet of an advanced fusion reactor and various HTS applications. In a previous study, we successfully achieved a joint resistivity of about 3.5 pΩm2 by heat treatment during fabrication of the joint. In this study, improved heat treatment method was developed by controlling contact pressure and combining bake-out process. We evaluated joint resistance and critical current of the joint depending on the heating condition and bake-out condition. The joint resistivity after heat treatment was 2.5 pΩm2 without decreasing critical current with conditions of heating temperatures of 90-140 °C, a heating time of 30 min, a contact pressure of 100 MPa, a bake-out time of 30 min, and a bake-out temperature of 150 °C. Owing to applying the contact pressure when the indium becomes softer, the true area of contact increased and the thickness of the indium decreased greater than those in the previous method. In addition, it was shown that voids appearing by heating were removed by bake-out process from thermal desorption spectroscopy test.

Original languageEnglish
Article number7862136
JournalIEEE Transactions on Applied Superconductivity
Volume27
Issue number4
DOIs
Publication statusPublished - 2017 Jun

Keywords

  • Fusion reactors
  • high-temperature superconductors (HTS)
  • power cable connecting
  • superconducting magnets

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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