No-insulation (NI) REBCO superconducting magnets allow very high engineering current density. Therefore, it can achieve very high magnetic field with a compact design. The considerable charging delay time due to current redistribution between turns in a pancake coil, however, limits its application to magnets that do not require frequent field ramps. Since long charging delay is directly linked to low contact resistance between turns, increasing contact resistance can mitigate the charging delay. On the other hand, very high contact resistance compromises the ability of self-quench-protection which is a crucial advantage of the NI technology. Therefore it is highly desirable to optimize the magnet performance and reliability by adjusting turn-to-turn contact resistance which might be achieved by coating REBCO with a thin layer of resistive material.
In this work, REBCO samples are coated respectively with a layer of nickel, chromium and copper oxide of varying thicknesses. Contact resistance between two coated REBCO tapes is measured at low temperatures as a function of load and load cycles. The results will be discussed in light of its applications in NI magnets.
Acknowledgement: Financial support of National Science Foundation Cooperative Agreement No. DMR-1157490 and the State of Florida