铁氧体、石墨及钢纤维水泥复合砂浆电磁屏蔽性能的实验研究

Study on Electromagnetic Shielding Properties of Ferrite,Graphite and Steel Fiber Cement Composite Mortars

利用同轴平面夹具-频谱分析仪法研究了掺铁氧体、石墨及钢纤维的水泥复合砂浆在100 kHz～1500 MHz频率范围内的电磁屏蔽效能。结果表明:同时掺加铁氧体、石墨及钢纤维的水泥基复合材料低频段的电磁屏蔽性能有明显提高,当钢纤维掺量为0.5%时,在200～1000 MHz频段内最低电磁屏蔽效能为13 dB,1000～1500 MHz屏蔽效能均大于20 dB,最大的屏蔽效能达到35 dB左右;复掺铁氧体-钢纤维或石墨-钢纤维均比单掺铁氧体、石墨或钢纤维试样的屏蔽效能有所改善,其中复掺锰锌铁氧体和钢纤维水泥基复合材料的屏蔽效能在钢纤维掺量为1%时达到45 dB左右。

The electromagnetic shielding properties of ferrite, graphite and steel fiber cement composite mortars were measured using the coaxial plane-spectrum analyzer method in the frequency range of 100 kHz-1500 MHz. The results showed that the electromagnetic shielding effectiveness （SE） of cementbased composites with ferrite, graphite and steel fiber was obviously increased in the low frequency range;when steel fiber content was 0.5vol %, the minimum SE can attain about 13 dB in the range of 200-1000 MHz, the SE was greater than 20 dB in the range of 1000-1500 MHz and the maximum SE can attain about 35 dB. The SE of specimens with ferrite and steel fiber or with graphite and steel fiber was more effectively improved compared to respectively with ferrite, graphite or steel fiber. Therefore, the SE of cement-based composites with Mn-Zn ferrite and steel fiber attained about 45 dB when steel fiber content was 1 vol%.