Study on the Mechanical Properties of Ice-Impregnated HTS Coils Formed Under Confining Pressure

Abstract

Epoxy resins are commonly used to impregnate the High temperature superconducting (HTS) coils for mechanical reinforcement. However, performance degradation of the epoxy impregnated HTS coils is inevitable due to the different thermal expansion coefficients between the epoxy resin and the HTS tape. The ice impregnation technique of pulsed magnets was applied to HTS coils for the first time. But cracks were easily formed in ice during cooling process and the mechanical strength of ice was rarely studied at 77 K. To solve this problem, we introduced the technique of ice impregnation under confining pressure into HTS coils. In this paper, uniaxial tension test, compression test and crack detection test of ice were conducted in liquid nitrogen. And critical current of the HTS coil was also measured under confining pressure at 77 K. The experimental results showed that ice impregnated HTS coil under confining pressure did not have performance decay in critical current and the mechanical strength was significantly improved.