Effect of Nano-doping on Breakdown Performance of B₄C/ETFE Nanodielectrics

Energetic electrons from the space can penetrate through the aluminum shield of spacecraft and deposit in the deep layer of insulating materials, leading to internal charging. When the space charge accumulation exceeds a certain threshold, Electric field distortion occurs, resulting in the failure of electronic equipment. The improvement of internal charging and discharging characteristics usually has a negative influence on dielectric breakdown of dielectrics. In this paper, nanodoping was applied as a valid method to promote the internal charging and discharging characteristics of dielectrics, without reducing dielectric breakdown performance. ¹Glass transition temperature, DC breakdown strength and surface potential decay of ethylene-tetrafluoroethylene copolymer (ETFE) with different nano-boron carbide (B₄C) doping ratios were tested. Experimental results illustrate that glass transition of B₄C/ETFE with different doping ratios are quite high, therefore dielectric breakdown is difficult to improve considering polymer molecular chain movement. Charge dissipation is enhanced while DC dielectric breakdown of ETFE changes slightly at doping ratios of 0.5%. B₄C can capture more carriers by introducing more deep traps, leading to electric distortion in dielectrics. Therefore, DC breakdown strength decreases. Charge dissipation is enhanced since more shallow traps is introduced, which help carriers migrate. Such changes are caused by the changed local structure of the polymers in interfacial regions. A potential approach is provided to promote the internal charging and discharging characteristics without decreasing dielectric breakdown of ETFE.