Surface flashover is a crucial issue for the miniaturisation of electronic facilities in military, industrial, and aerospace engineering. The oriented hexagonal boron nitride (hBN) composites, due to excellent thermal and electrical insulating properties, show a potential application in high-voltage power equipment, while the surface flashover performance of hBN composites dependent on oriented hBN texture is rarely reported. The effects of hBN orientation and contents on the surface flashover performances of oriented hBN composites are investigated. The isothermal surface potential decay of the oriented hBN composites was also studied. It is found that the charge transportation could be adjusted by the hBN orientation, thus regulating surface flashover strength. The DC flashover voltage of the in-plane oriented hBN composites with a thickness of 15 μm reached the maximum of 27.6 kV at the hBN loading of 20 wt%, 14.5% higher than that of the pure resin. The carrier mobility of out-of-plane oriented hBN composites is about three times greater than that of the in-plane oriented composites, indicating that the charges are easily transported along the hBN basal plane. The larger carrier mobility causes charge dissipation in composites near the electrode at the hBN basal plane parallel to the axis of electrodes and inhibits the distortion of the surface electric field on the composites, thus enhancing the surface flashover. Consequently, developing oriented insulators for high-voltage applications and enabling an optimum insulation design would be beneficial because of the compactness and high reliability of power apparatus for use in power grids.

中文翻译：

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通过各向异性电荷传输增强取向六方氮化硼复合材料的表面闪络性能

表面闪络是军事、工业和航空航天工程中电子设施小型化的一个关键问题。取向六方氮化硼（hBN）复合材料由于具有优异的隔热和电绝缘性能，在高压电力设备中显示出潜在的应用前景，而六方氮化硼复合材料的表面闪络性能依赖于取向六方氮化硼织构的报道却很少。研究了六方氮化硼取向和含量对取向六方氮化硼复合材料表面闪络性能的影响。还研究了取向六方氮化硼复合材料的等温表面电势衰减。研究发现，六方氮化硼的取向可以调节电荷传输，从而调节表面闪络强度。厚度为15 μm的面内取向六方氮化硼复合材料的直流闪络电压在六方氮化硼负载量为20 wt%时达到最大值27.6 kV，比纯树脂高14.5%。面外取向的六方氮化硼复合材料的载流子迁移率大约是面内取向复合材料的三倍，这表明电荷很容易沿着六方氮化硼基面传输。较大的载流子迁移率导致复合材料在平行于电极轴的六方氮化硼基面附近的电极处发生电荷耗散，抑制了复合材料表面电场的畸变，从而增强了表面闪络。因此，由于电网中使用的电力设备的紧凑性和高可靠性，开发用于高压应用的定向绝缘子并实现最佳绝缘设计将是有益的。