Dielectric properties of MgO/Epoxy nanocomposites in liquid nitrogen environment

Abstract

As the epoxy resin material of superconducting equipment is often in low temperature environment, the insulation properties of epoxy resin changes with temperature accordingly which brings new problems on insulation design of superconducting equipment. This paper studied the effect of nano-MgO particles on the dielectric properties of epoxy resin in liquid nitrogen condition. We used magnesium oxide particles with average size of 50nm and 80nm mixed with epoxy resin to obtain different doping amount of composite dielectric and prepared pure epoxy resin samples as comparison. The test results showed that the addition of nanoparticles enhanced the breakdown strength of the epoxy resin compared to the pure epoxy samples. The breakdown strength in liquid nitrogen condition was higher than the breakdown strength at normal temperature. Dielectric properties test results showed that the dielectric constant of epoxy resin in liquid nitrogen environment was lower than that at normal temperature, and the addition of nanoparticles decreased the dielectric constant of epoxy resin. The dielectric loss was greatly influenced by temperature, and it will decrease significantly in low temperature environment. The research provides important reference value for the insulation design of superconducting equipment.