Space Charge Dynamics in Epoxy Based Composites Under DC and Square Pulse Wave of Different Polarities and Frequencies

Space charge dynamics of epoxy based micro-nano hybrid composites under DC and square pulse waves of different polarities and frequencies are investigated. A specially designed high-speed pulsed electro-acoustic (PEA) system is adopted to measure the space charge distributions of the prepared samples under different DC and square pulse voltage with positive and negative polarity. The DC electric field and the square pulse electric field of 20 kV/mm and 40 kV/mm with different polarities and frequencies are used. The results show that the micro-nano filler addition can suppress the space charge accumulation during the polarization. Furthermore, it can facilitate the dissipation of the accumulated charges during depolarization. No polarity effect is found in both samples under DC electric field. More space charges are accumulated in both samples under positive square pulse voltage with lower frequency, whereas the negative square pulse voltage with the higher frequency accelerates space charge accumulation in both samples. Moreover, the negative voltage has a more evident effect than the positive electric field on both samples. The space charge suppression effect of the micro-nano fillers is reduced under the square pulse voltage compared to the DC voltage. It is elucidated that epoxy based micro-nano hybrid composites are potential packaging materials for electronic devices. Still, their performance under the negative square pulse voltage with the high frequency and the positive square pulse voltage with the low frequency needs to be further investigated.