作者：Yongqiang Guo, Hua Qiu*, Kunpeng Ruan, Shuangshuang Wang, Yali Zhang and Junwei Gu*
关键字：Thermally conductive composites
论文来源：期刊
具体来源：Composites Science and Technology
发表时间：2022年

High integration development of electronics requires materials possessing excellent thermal conductivity, electromagnetic interference (EMI) shielding, and electrical insulation. In this work, Fe2O3 particles are deposited on carbon fibers (CF) and then utilized as fillers (CF@Fe2O3) in boron nitride/silicone rubber (BN/SR) to fabricate sandwich structured CF@Fe2O3/(BN/SR) composites, herein, BN/SR as top & substrate layer, and CF@Fe2O3 as middle layer. Orientation of BN in CF@Fe2O3/(BN/SR) composites realizes excellent in-plane thermal conductivity coefficient (λ∥), and the core-sheath structure of CF@Fe2O3 achieves good EMI shielding performance by the “absorption-reflection (transmittance)-reabsorption” process of electromagnetic waves, insulation modification of CF and the sandwich structure strengthen the electrical insulation. When the amount of BN and CF@Fe2O3 are 20.6 wt% and 45.5 wt%, respectively, the λ∥, EMI shielding effectiveness, volume resistance and breakdown strength of CF@Fe2O3/(BN/SR) composites reach 3.86 W/(m·K), 37.7 dB, 6.2×1014 Ω·cm and 26.8 kV/mm, respectively, which are all higher than those of commonly fabricated CF/(BN/SR) composites with same amount of BN and CF (3.83 W/(m·K), 19.4 dB, 8.6×1013 Ω·cm and 21.4 kV/mm). CF@Fe2O3/(BN/SR) composites possess better cooling effect (5.6oC) than that of commercial silicon grease (QM850) on the testing platform of computer’s central processing unit, whose functions are more abundant and have wide application prospects in electronics.

电子产品高集成化的发展趋势亟需兼具优异导热、电磁屏蔽且电绝缘的材料。本文以硅橡胶（SR）为基体，氮化硼（BN）为导热填料，通过在碳纤维（CF）表面沉积Fe2O3制备CF@Fe2O3，再采用刮涂法制备上下层为BN/SR、中间层为CF@Fe2O3的三明治结构CF@Fe2O3/(BN/SR)复合材料。BN在CF@Fe2O3/(BN/SR)复合材料面内方向的取向排列赋予其优异的面内导热性能；芯鞘结构的CF@Fe2O3使电磁波能够被“吸收-反射（透过）-再吸收”，实现其优异的电磁屏蔽性能；CF表面绝缘化和上下层绝缘的三明治结构保证其优异的绝缘性能。当BN和CF@Fe2O3用量分别为20.6 wt%和45.5 wt%时，CF@Fe2O3/(BN/SR)复合材料的面内导热系数、电磁屏蔽效能、体积电阻率和击穿强度分别为3.86 W/(m·K)、37.7 dB、6.2×1014 Ω·cm 和26.8 kV/mm，其综合性能明显优于同等BN和CF用量下制备的CF/(BN/SR)复合材料（3.83 W/(m·K)、19.4 dB、8.6×1013 Ω·cm 和21.4 kV/mm）。此外，CF@Fe2O3/(BN/SR)复合材料比市售的高导热硅脂（QM850）更能有效降低实际工况下CPU的工作温度（降幅约5.6oC），且功能更加丰富，在电子电气等领域具有广泛的应用前景。