[IEEE 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Budapest (2018.7.1-2018.7.5)] 2018 IEEE 2nd International Conference on Dielectrics (ICD) - High Voltage Electrical Properties of Epoxy / h-BN Microcomposites

摘要： Two high voltage properties – DC conductivity and AC breakdown strength – of epoxy composites filled with 30 wt% of micron sized hexagonal boron nitride (h-BN) are discussed in comparison to neat epoxy. The influence of h-BN upon the field dependence of DC conductivity has been studied up to 18 kV/mm. The addition of h-BN does not lead to a modification of conduction mechanisms: the J-V characteristics show an ohmic behavior at low fields and a space charge limited current (SCLC) at higher fields for both neat epoxy and composite. However, the addition of 30 wt% h-BN reduces the overall electrical conductivity and increases the threshold voltage between ohmic and SCLC regions, leading to a significant modification of electrical conductivity within the field range compared to neat epoxy. AC breakdown strength is enhanced for epoxy – h-BN composites while generally speaking the addition of micro fillers in an epoxy matrix tends to decrease it.