Chang Xizhe, Sui Yueyi, Li Changyu, Yan Zhanyuan
Department of Mathematics and Physics, North China Electric Power University, Baoding 071000, China.
State Grid Hebei Electric Power Co., Ltd. Ultra High Voltage Branch, Shijiazhuang 050070, China.
Nanomaterials (Basel). 2024 Aug 24;14(17):1382. doi: 10.3390/nano14171382.
To conquer the challenges of charge accumulation and surface flashover in epoxy resin under direct current (DC) electric fields, numerous efforts have been made to research dielectric barrier discharge (DBD) plasma treatments using CF/Ar as the medium gas, which has proven effective in improving surface flashover voltage. However, despite being an efficient plasma etching medium, SF/Ar has remained largely unexplored. In this work, we constructed a DBD plasma device with an SF/Ar gas medium and explored the influence of processing times and gas flow rates on the morphology and surface flashover voltage of epoxy resin. The surface morphology observed by SEM indicates that the degree of plasma etching intensifies with processing time and gas flow rate, and the quantitative characterization of AFM indicates a maximum roughness of 144 nm after 3 min of treatment. Flashover test results show that at 2 min of processing time, the surface flashover voltage reached a maximum of 19.02 kV/mm, which is 25.49% higher than that of the untreated sample and previously reported works. In addition to the effect of surface roughness, charge trap distribution shows that fluorinated groups help to deepen the trap energy levels and density. The optimal modification was achieved at a gas flow rate of 3.5 slm coupled with 2 min of processing time. Furthermore, density functional theory (DFT) calculations reveal that fluorination introduces additional electron traps (0.29 eV) and hole traps (0.38 eV), enhancing the capture of charge carriers and suppressing surface flashover.
为了克服直流（DC）电场下环氧树脂中电荷积累和表面闪络的挑战，人们已经做出了许多努力来研究以CF/Ar作为介质气体的介质阻挡放电（DBD）等离子体处理，事实证明这在提高表面闪络电压方面是有效的。然而，尽管SF/Ar是一种高效的等离子体蚀刻介质，但在很大程度上仍未得到充分研究。在这项工作中，我们构建了一个以SF/Ar气体为介质的DBD等离子体装置，并探讨了处理时间和气体流速对环氧树脂形态和表面闪络电压的影响。扫描电子显微镜（SEM）观察到的表面形态表明，等离子体蚀刻程度随处理时间和气体流速的增加而加剧，原子力显微镜（AFM）的定量表征表明，处理3分钟后最大粗糙度为144纳米。闪络测试结果表明，在处理时间为2分钟时，表面闪络电压最高达到19.02 kV/mm，比未处理样品和先前报道的工作高出25.49%。除了表面粗糙度的影响外，电荷陷阱分布表明氟化基团有助于加深陷阱能级和密度。在气体流速为3.5 slm且处理时间为2分钟的条件下实现了最佳改性。此外，密度泛函理论（DFT）计算表明，氟化引入了额外的电子陷阱（0.29 eV）和空穴陷阱（0.38 eV），增强了对电荷载流子的捕获并抑制了表面闪络。
