Pulsed vacuum flashover properties of micro and nano Al2O3·3H2O/epoxy composites

Micro and nano Al₂O₃middot3H₂O fillers are loaded into the epoxy resin by mixing different weight ratio. The flashover studies were conducted using three kinds of nanosecond rise pulse under 5 times 10^-3 Pa vacuum. The surface flashover properties of nano and micro Al₂O₃middot3H₂O/epoxy composites are presented. The influence of filler size and content on the interface structure, interface layer distribution and interface volume proportion was discussed. The relationship between particle size influence and flashover voltage was analyzed. A deep and shallow trap model based on the multi-layer model was proposed. Considering the size influence of fillers, the flashover characteristic was able to be explained.