Isothermal Discharge Current and Trap Characteristics of Epoxy Resin at Low Temperature

Abstract Epoxy resin has been commonly used as a supporting and insulating material in superconducting systems which operate at low temperatures and high electric fields. However, it has diverse and complex internal defects. The traps within epoxy resin can capture space charges, especially under factors like radiation and Schottky injection. This can affect the material’s performance in terms of mechanical and breakdown strength. In this study, a Corona injection was performed using a needle-plate electrode. The isothermal discharge current method (IDC) was used to test a bisphenol F epoxy resin sample (using DETD as a curing agent) with a thickness of 0.14 mm. The migration characteristics of space charges were investigated at both 77 K and room temperature, and the trap characteristics at different temperatures were obtained. The results indicate that temperature has a negative effect on the intrinsic conductance current, dipole polarization current, and de-trapping current. This suggests that the trap properties of epoxy resins are strongly influenced by temperature.