掺镍纤维的水泥基复合材料的电磁屏蔽性能

Electromagnetic Shielding Properties of Cement-based Composites by Doping Nickel Fibre

电磁波技术的广泛应用导致电磁干扰与污染日益严重,采取电磁屏蔽措施能够有效地防范这些危害。实验采用不同的方法分散镍纤维屏蔽介质,然后掺入到水泥材料中制得水泥基复合屏蔽材料,研究了屏蔽介质的分散方式、掺量、试样厚度对屏蔽性能的影响;利用四探针测试仪、电子探针等手段表征了复合材料的电导率和屏蔽介质的分散均匀性。结果表明,镍纤维屏蔽介质的分散方式对屏蔽性能有较大的影响,其在水泥基材料中有一个最佳掺量值;当采用超声波分散的掺量φ镍纤维为5%、试样厚度为6 mm时,水泥基复合材料的电导率为2. 41×10^(-3)S/cm,在100 k Hz～1. 5 GHz频率范围内的平均屏蔽效能值约40 d B,其最小屏蔽效能值为36. 23 d B,最大达45. 74 dB。

The disturbing and pollution of electromagnetic wave have been increasingly severity by application of electromagnetic wave technique, and this harm can be prevented through using electromagnetic shielding method. The nickel fibre is dispersed by different method, such as ultrasonic disperse and blend with cement, and the cement-based composites shielding materials is made of cement and nickel fibre. The effection of dispersive manner and contents of shielding medium, thickness of specimens on electromagnetic shielding properties are researched. The conductivities of cement-based composites are tested by four-point probe meter and the uniformity distribution of shielding medium are determined using electron probe X-ray microanalyzer. The experiment results indicate that the effect of distributed method of nickel fibre on shielding properties is greater and its contents in cement-based materials has one optimal number. When the contents of nickel fibre by ultrasonic dispersed is 5%(φ Ni ) and thickness of specimens is 6 mm, the conductivity of cement-based composite materials is 2.41×10 -3 S/cm. The average shielding effectiveness is about 40 dB in 100 kHz^1.5 GHz frequency range, the least and maximum shielding effectiveness are 36.23 dB and 45.74 dB respectively.