抄録
In this paper, we report on dielectric breakdown characteristics of alumina-filled epoxy resin irradiated by γ-ray under a needle-plane electrode geometry. For that purpose, we studied relationship between breakdown voltage and filler parts, relationship between breakdown voltage and irradiation dose, and an influence of thickness of epoxy resin on breakdown voltage. In order to investigate these results, we made further experiments on Glass Transition Temperature change before and after γ-ray irradiation using a DSC method, and filler parts dependence of tan δ and ε We also investigated surface oxidization of epoxy resin from a wave analysis of spectra measured using FT-IR difference spectro-meter, We observed surfaces of epoxy resin before and after γ-ray irradianon using a Scanning Electron Microscope (SEM). The results are as follows: 1) In the case of 2mm thick, dielectric breakdown voltage of epoxy resin increases suddenly from 5 parts to 40 parts, and decreases slowly from 40 parts to 300 parts, under both positive and negative impulse voltage. 2) Dielectric breakdown voltage of epoxy resin with 2mm thick begins to decrease at 2MGy under positive impulse voltage, but it begins to decrease at 5MGy under negative impulse voltage.
