基于氧化铝/羰基铁粉的复合贴片吸波与导热特性分析

Electromagnetic wave absorption and thermal conduction characteristics of composite sheets containing aluminum oxide/carbonyl iron powders

分别以羰基铁粉和氧化铝粉作为功能填料、丁腈橡胶作为基材制备了系列复合吸波贴片,对样品的微观形貌、电磁参数以及热导率进行了测试表征,分析了羰基铁粉和氧化铝粉用量比例调整对复合贴片吸波与导热性能的影响。结果表明,随着羰基铁粉含量减小、氧化铝粉含量相应增大,复合贴片的复介电常数和复磁导率实部、虚部总体上均呈减小的趋势;反射损耗峰的位置移向高频,衰减系数均随频率的升高逐渐增大,同一频率下羰基铁粉含量越高的样品衰减系数越大;复合贴片的热导率呈先上升后下降的趋势;考察的样品均表现出宽带强吸收特性,样品热导率的相对较高值为~1.66 W/(m·K)。通过两种填料的粒径和体积分数匹配设计进行界面特性优化,可有效调控复合贴片的电磁参数、减小界面热阻,实现对复合贴片吸波与导热性能的兼顾提升。

A series of composite sheets were fabricated with aluminum oxide powders(Al2O3), carbonyl iron powder(CIP) as functional fillers and acrylonitrile-butadiene rubber as binder, respectively. The morphology, electromagnetic parameters and thermal conductivity of the samples were characterized. The influences of the mass ratio of CIP to Al2O3 on the electromagnetic wave absorption and thermal conductivity of the composite sheets were discussed. The results show that the real and imaginary parts of complex permittivity and complex permeability decrease with the reduction of CIP and the increase of Al2O3 in the composite sheets. The position of reflection loss(RL) peak shifts toward higher frequencies accordingly. Meanwhile, the attenuation coefficient of the composite sheets exhibit enhancing trend with the increase of frequency, and possess larger values at a certain frequency with higher content of CIP. Furthermore, the thermal conductivity of the composite sheets increases initially, and then decreases with decreasing mass ratio of CIP to Al2O3. All the samples obtain the characteristics of broadband strong absorption, and relatively high thermal conductivity reaches at about 1.66 W/(m·K). This work clearly shows that we can effectively manipulate the electromagnetic parameters and reduce interface thermal resistance with optimized interface characteristics through the matching design of the particle size and volume fraction of the two fillers, so as to simultaneously improve the performances of electromagnetic wave absorption and thermal conduction for such polymer composites.