Flashover characteristic of epoxy composites filled with different micro-inorganic oxide particles under nanosecond pulse in vacuum

Research on the vacuum surface flashover mechanisms of insulating material under nanosecond pulses is important for the design and manufacture of high-power pulse generators. Here, the vacuum surface flashover characteristic of epoxy composites filled with different microfillers Al₂O₃·3H₂O, Al₂O₃, BaTiO₃, and TiO₂ is investigated using a unipolar pulse generator (50-ns rise time and 600-ns full-width at half-maximum). In addition, their thermally stimulated depolarization current and secondary electron emission (SEE) coefficients are measured. The results show that the flashover performance does not depend just on the SEE coefficient, but that the different effects of shallow and deep traps must also to be taken into account.