Synergic realization of electrical insulation and mechanical strength in liquid nitrogen for high-temperature superconducting tapes with ultra-thin acrylic resin coating

Abstract

Insulation coating is a sought after technique for REBa2Cu3O6+x (REBCO) based high temperature superconducting tapes in practical applications. In this work, we developed a novel technique for preparing ultra-thin and fully surrounded insulation coatings on REBCO tapes. This technique completely eliminates the risk of critical current degradation in REBCO tapes induced by high temperature curing, without sacrificing the mechanical performance and the engineering current density. We adopted CRC-PLASTICOTE-70 as insulation precursor and verified its performance as insulation coating at 77 K. Thickness effect of the insulation coating in liquid nitrogen was investigated in details. Ultra-thin coating (below 5 μm) on REBCO tapes exhibited excellent strength during thermal shock test, while good adhesion of classification 1 was achieved (according to ISO2409-1992). A charge–discharge test was carried out on a test coil wound from as-coated tapes to assess the turn-to-turn insulation performance. The results show that a high turn-to-turn resistivity of 1060 μΩ cm2 is achieved by the insulation coating, which is about two orders of magnitude higher than that of its un-coated counterpart, indicating excellent insulation properties. This work provides a new idea for the development of novel insulation technology for REBCO tapes in practical applications.