核壳结构BNNS@SiO_(2)/环氧复合电介质的电-热击穿特性

Electric-thermal breakdown properties of core-shell structure BNNS@SiO_(2)/epoxy composite dielectric

本文制备不同填料含量的核壳结构BNNS@SiO_(2)/环氧复合电介质,研究复合电介质界面区的化学特征与微观形貌,通过热刺激去极化电流法与击穿测试研究环氧复合电介质的陷阱特性与击穿性能。结果表明:BNNS@SiO_(2)具有核壳结构,且包覆的SiO_(2)厚度在纳米级别;BNNS@SiO_(2)表面存在明显化学键合作用,与环氧基体可形成较强的界面区,提升其与环氧基体的相容性。少量BNNS@SiO_(2)可有效提升复合电介质的电气强度,当BNNS@SiO_(2)的质量分数为1%时,复合电介质的电气强度可提升52.3%。当BNNS@SiO_(2)纳米粒子含量较少时,环氧复合电介质中的深陷阱增加,当纳米粒子含量较多时,深陷阱数量有所减少,浅陷阱数量增加。此外,核壳结构BNNS@SiO_(2)/环氧复合电介质的热导率明显提高,有利于高电场下的绝缘散热。通过深陷阱效应与导热性能提升的综合作用,环氧复合电介质的击穿性能得到显著提升。

In this paper,BNNS@SiO_(2)/epoxy composite dielectrics with different filler content were prepared,the chemical characteristics and microscopic morphology of the composite dielectrics interface area were studied,and the trap characteristics and breakdown properties of the composite dielectrics were studied by thermal stimulation depolarization current method and breakdown test.The results show that BNNS@SiO_(2) has a core-shell structure and the thickness of the coated SiO_(2) is at the nanoscale.There is a clear chemical bonding effect on the surface of BNNS@SiO_(2),which can form a strong interface zone with the epoxy matrix,so as to improve its compatibility with the epoxy matrix.A small amount of BNNS@SiO_(2) can effectively improve the electric strength of the composite dielectric,and when the mass fraction of BNNS@SiO_(2) is 1%,the electric strength of the composite dielectric increases by 52.3%.When the content of BNNS@SiO_(2) nanoparticles is small,the deep traps in the epoxy composite dielectric increases.When content of BNNS@SiO_(2) nanoparticles is large,the deep traps decrease and the shallow traps increase.In addition,the thermal conductivity of the core-shell structure BNNS@SiO_(2)/epoxy composite dielectric increases significantly,which is conducive to the heat dissipation of insulation under high electric field.Through the comprehensive effect of deep trap effect and thermal conductivity improvement,the breakdown performance of epoxy composite dielectric is improved significantly.