This study introduces silicone elastomers with micro and nano-sized boron nitride (BN) and silicon carbide (SiC) particles with various doping levels to improve thermal properties and partial discharge resistance. The effect of micro and nano-fillers on thermal conductivity, coefficient of thermal expansion (CTE), and thermal stability are investigated. Polarization and depolarization current and partial discharge are measured to investigate the non-linear conductivity, trap energy density distribution, and partial discharge resistance. Experimental results show higher thermal conductivity, lower CTE, and better thermal stability than the original silicone elastomer. Large size fillers dominate the thermal conductivity when the doping level is low, whereas the composite microstructure plays a significant role in the thermal conductivity when the doping level is high. The combination of different filler type and size has less effect on thermal stability and CTE compared to the effect of the doping level. According to the depolarization current, the composite's trap depth is generally shallower than that of the original silicone elastomer. With increased doping level, the shallow trap density increases, providing hopping sites for carriers, whereas the deep trap density decreases, reducing the number of trapped charges. The partial discharge inception voltage is higher than that of the original silicone elastomer, and it increases with the doping level, which may be because the electrostatic field generated by diffused charges reduces the local electric field near the high voltage electrode.

中文翻译：

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微纳米尺寸氮化硼和碳化硅对有机硅弹性体复合材料热性能和耐局部放电性能的影响

本研究引入了具有各种掺杂水平的微米和纳米尺寸的氮化硼 (BN) 和碳化硅 (SiC) 颗粒的有机硅弹性体，以提高热性能和抗局部放电性能。研究了微米和纳米填料对热导率、热膨胀系数 (CTE) 和热稳定性的影响。测量极化和去极化电流和局部放电，以研究非线性电导率、陷阱能量密度分布和局部放电电阻。实验结果表明，与原始有机硅弹性体相比，具有更高的导热性、更低的 CTE 和更好的热稳定性。当掺杂水平低时，大尺寸填料占主导地位，而当掺杂水平高时，复合材料的微观结构对热导率起着重要作用。与掺杂水平的影响相比，不同填料类型和尺寸的组合对热稳定性和 CTE 的影响较小。根据去极化电流，复合材料的陷阱深度通常比原始有机硅弹性体的陷阱深度浅。随着掺杂水平的增加，浅陷阱密度增加，为载流子提供跳跃位置，而深陷阱密度降低，减少了被困电荷的数量。局部放电起始电压比原来的有机硅弹性体高，并且随着掺杂水平的增加而增加，