碳纤维增强水泥基复合材料的吸波性能研究

利用弓形反射法(NRL)测试了碳纤维掺量分别为0.2%、0.4%、0.6%、0.8%和1.0%(质量分数)时碳纤维增强水泥基复合材料(CFRC)在低频段4～8GHz和高频段8～18GHz时的反射率,讨论了纤维掺量、频率、反射率之间的关系.结果发现,在纤维掺量相同条件下:低频段时,反射率＜-10dB,CFRC表现出吸波性;高频段且纤维掺量超过0.6%(质量分数)时,反射率＞-10dB,CFRC对电磁波表现出反射性.随着纤维掺量的增加,低频段时反射率先降低、后又有所回升,吸波性由弱变强、又变弱,纤维掺量为0.6%(质量分数)时出现最小反射率-15.0dB;高频段时反射率总体上呈上升趋势,材料对电磁波的反射性越来越强,纤维掺量为0.4%(质量分数)时出现最小反射率-19.4dB.

Study on microwave-absorbing properties of carbon-fiber-reinforced cement-based composites

The reflectivity of carbon-fiber-reinforced cement-based composites(CFRC) in the frequency ranges of 4 to 8GHz and 8 to 18GHz was measured using the naval research laboratory(NRL) testing system when the carbon fiber content was 0.2wt%,0.4wt%,0.6wt%,0.8wt%,and 1.0wt%,respectively. The reflectivity data in two different frequency ranges were compared when the fiber content kept constant.The variation of reflectivity in the same frequency range was discussed when carbon fiber content increased.Results show that the reflectivity is less than-10dB in the lower frequency range and the composites exhibit microwave-absorbing properties.However,the reflectivity is above-10dB in the higher frequency range after the percentage of 0.6wt% and they exhibit the microwave-reflecting properties.As the fiber content rose,the reflection loss at different frequency ranges varied differently: the minimum reflectivity in the lower frequency range was-15.0dB at 0.6wt%,while that in the higher frequency range was-19.4dB at 0.4wt%.