Insulation for Wind and React High Temperature Superconducting Coils

Abstract

A thin, thermally stable, well-adhered insulation is needed for the fabrication of High Temperature Superconducting (HTS) coils. Due to the brittle nature of HTS materials the Wind and React (W & R) approach is employed. Therefore one has to use high temperature compatible insulating material for providing the turn to turn electrical insulation in the W&R HTS coils. A sol-gel ceramic based insulation coating process has been developed at the National High Magnetic Field Laboratory (NHMFL) for providing such insulation. Optical microscopy, Environmental Scanning Electron Microscopy (ESEM), and X-Ray Diffraction (XRD) were used to study the microstructure and phase composition of insulation coatings obtained. A stack of six double pancakes which was fabricated using this sol-gel insulation coating for turn-to-turn electrical insulation produced 1.2 T in a background field of 17.5 T at 4.2K.