碳泡沫吸波性能的研究

制备了具有三维网络结构的泡沫碳材料并研究了其吸波性能。结果表明：碳泡沫的电导率随着其热解温度的提高而增加。碳泡沫的电导率对其吸波性能有重要影响。随着电导率从0．02S／cm提高到1．03S／cm，碳泡沫对入射电磁波从透波为主转变为反射为主，吸波性能先逐渐变好，然后又逐渐变差。对于1.0mm网孔尺寸、30％体积分数和15mm厚度的碳泡沫来说，电导率为0．46S／cm时具有最佳的吸波性能，在4～15GHz整个频段上的反射率均在-6dB以下，体现了宽频带的吸收特征。碳泡沫的网孔尺寸、体积分数和厚度均对其吸波性能有一定影响。

Microwave absorbing performance of a carbon foam

Carbon foam with a reticulate structure was fabricated through polymer sponge replication process and its microwave wave absorbing performance was investigated with detail. It was found that the electric conductivity of carbon foam increases as the carbonization temperature rises. Moreov.er the conductivity of carbon foam strongly influences its microwave wave absorbing properties. As the conductivity of carbon foam increases from 0.02 S/m to 1.03 S/m, carbon foam changes from electromagnetic wave transmission mainly to reflection dominantly, hence the microwave absorbing performance of carbon foam improves firstly and then deteriorates. The best microwave absorbing performance was achieved for carbon foam with 1.0mm cell size, 30% volume fraction and 15mm thickness when its conductivity is 0.46S/m, as the reflection coefficient for the carbon foam has reached --6dB within the whole frequency range. Here carbon foam has demonstrated a wide bandwidth absorbing characteristic that is rarely obtained for conventional microwave absorbing materials without any impedance match design. The cell size, volume fraction and thickness all have some influence on the microwave absorbing property of carbon foam.