Effects of Electron Beam Irradiation on Insulation Characteristics of Epoxy/AlN Nanocomposites

Superconducting magnet is one of the core components of international thermonuclear experimental reactor (ITER). Due to the harsh operating environment, for the sake of ensuring the stable operation of the superconducting magnet, the superconducting magnet insulation is required to have excellent electrical and irradiation resistance. However, pure epoxy resin is difficult to adapt to the harsh environment in the ITER, so it needs to be modified to improve its insulation performance. In this paper, the epoxy/AlN nanocomposites with 1 wt% filler content of AlN nanoparticles were prepared, and the dispersion of nanoparticles was observed. High-energy electron beam was used to treat nanocomposites with the dose of 300, 500, and 700 kGy. The relative permittivity and conductivity of the nanocomposites after irradiation were tested. In addition, the data of surface potential were measured after surface charging for analyzing the dynamic behavior of surface charge and calculating the trap distribution of the nanocomposites with various irradiation doses. The flashover voltage of the nanocomposites influenced by irradiation in LN2 was also analyzed. The results show that irradiation can cause the change of trap distribution and flashover voltage, and the change trend is not monotonous.