Corona discharge always threatens the safe and long-term operation of electrical equipment. Therefore, it is imperative to improve the corona resistance of electrical insulation materials. In this research work, fumed silica (SiO₂) with different particle sizes and self-made organic silicon–boron composite oxide (Si–B) are used to modify epoxy resin (EP) for enhancing the corona resistance. Si–B/SiO₂/EP nanocomposites with different SiO₂ content series and 4 kinds of SiO₂ particle size series are prepared by grinding machine dispersing and thermal curing. A strong dependence of the corona resistance on SiO₂ filler size in nano-scale and content is revealed experimentally. The filler combination of Si–B and nano-SiO₂ can reduce the relative permittivity of the Si–B/SiO₂/EP nanocomposites and inhibit the increase of dielectric loss. With the particle size of SiO₂ filler increases, the space charge suppression effect and the thermal stability are reduced, but corona resistance life is improved.When the 15-nm SiO₂ content is 15 wt%, the corona resistance life of the Si–B/SiO₂/EP nanocomposites can reach 8.99 h under 90 °C and 80 kV/mm electric field strength, while pure epoxy is only 0.86 h. The degradation path through the material is the more important factor affecting corona resistance performance–large particle size and well dispersion state can effectively extend the degradation path through the material.

电晕放电始终会威胁电气设备的安全和长期运行。因此，必须提高电绝缘材料的耐电晕性。在这项研究工作中，使用具有不同粒径的气相法二氧化硅（SiO ₂）和自制的有机硅-硼复合氧化物（Si–B）来改性环氧树脂（EP）以增强耐电晕性。通过研磨机分散和热固化制备了具有不同SiO ₂含量系列和4种SiO ₂粒径系列的Si–B / SiO ₂ / EP纳米复合材料。耐电晕性与SiO _2的强烈相关性实验揭示了纳米级的填料尺寸和含量。Si–B和纳米SiO ₂的填料组合可以降低Si–B / SiO ₂ / EP纳米复合材料的相对介电常数，并抑制介电损耗的增加。随着SiO ₂填料粒径的增加，空间电荷抑制效果和热稳定性降低，但耐电晕性提高。当15 nm SiO ₂含量为15 wt％时，Si–硼/ SiO ₂/ EP纳米复合材料在90°C和80 kV / mm的电场强度下可以达到8.99 h，而纯环氧仅为0.86 h。通过材料的降解路径是影响耐电晕性能的更重要因素-大粒径和良好的分散状态可以有效地扩展通过材料的降解路径。