La_(0.7)Sr_(0.3)MnO_(3)/α-Fe_(2)O_(3)复合材料的制备及吸波性能研究

Study on the preparation and electromagnetic wave absorbing properties of La_(0.7)Sr_(0.3)MnO_(3)/α-Fe_(2)O_(3) composite materials

以高温煅烧法制备了复合材料La_(0.7)Sr_(0.3)MnO_(3)/α-Fe_(2)O_(3),并研究了其结构、电磁参数和吸波性能,进一步初步探索了该粉体用于布料涂层的吸波效果。结果发现:La_(0.7)Sr_(0.3)MnO_(3)/α-Fe_(2)O_(3)与石蜡以质量比7∶3混合后的吸波性能显著,分别在厚度5.0和9.5 mm处能吸收99.9%以上的入射电磁波,吸波性能优异。此外,在1~18 GHz和1.0~10 mm范围内,样品La_(0.7)Sr_(0.3)MnO_(3)/α-Fe_(2)O_(3)的总有效吸收(≦-10 dB)带宽覆盖测试带宽的91.8%,实现了雷达多频段的有效吸收。复合材料良好的吸波性能得益于La_(0.7)Sr_(0.3)MnO_(3)和α-Fe_(2)O_(3)的介电损耗和磁损耗的共同作用,实现对电磁波的有效吸收。涂层法和平纹编制法制备的布料在5.84 GHz处也可以吸收90%以上的入射电磁波,为复合吸波材料及吸波织物的设计研究提供了新思路。

Composite material La_(0.7)Sr_(0.3)MnO_(3)/α-Fe_(2)O_(3) was prepared by high-temperature calcination method and its structure,electromagnetic parameters,and electromagnetic wave absorption performance were studied.Further preliminary exploration was conducted on the electromagnetic wave absorption effect of this powder for fabric coatings.The results showed that the significant absorption performance of La_(0.7)Sr_(0.3)MnO_(3)/α-Fe_(2)O_(3) is achieved when the powder and paraffin are mixed in a mass ratio of 7:3,and they can absorb over 99.9% of incident electromagnetic waves at a thickness of 5.0 mm and 9.5 mm,respectively.The absorption performance is excellent.In addition,within the range of 1-18 GHz and 1.0-10 mm,the total effective absorption(≦-10 dB) bandwidth of the sample La_(0.7)Sr_(0.3)MnO_(3)/α-Fe_(2)O_(3) covers 91.8% of the test bandwidth,achieving effective absorption of radar multi frequency bands.The excellent absorption performance of composite materials is attributed to the La_(0.7)Sr_(0.3)MnO_(3) and α-Fe_(2)O_(3).The combined effect of dielectric loss and magnetic loss of La_(0.7)Sr_(0.3)MnO_(3)/α-Fe_(2)O_(3) achieves effective absorption of electromagnetic waves.The fabrics prepared by coating method and plain weave methods can also absorb more than 90% of incident electromagnetic waves at 5.84 GHz,providing new ideas for the design and research of composite absorbing materials and absorbing fabrics.