双损耗Al_(2)O_(3)基多孔吸波材料的制备及其吸波性能

Fabrication and Microwave Absorbing Performance of Porous Al_(2)O_(3) Ceramic With Double Loss of Electromagnetic Wave

基于片状Al_(2)O_(3)陶瓷互锁结构强度高的特点,制备出夹杂石墨的高气孔率的Al_(2)O_(3)多孔陶瓷,并通过原位还原在多孔骨架中制备出Ni微粒,形成一种轻质的双损耗陶瓷基吸波材料。通过XRD、FE-SEM和EDS研究了还原温度对多孔吸波材料的组成、微观形貌、元素分布和吸波性能的影响。结果表明,还原温度升温至700℃可将多孔网络中Ni完全还原,形成以堆叠互锁Al_(2)O_(3)为基,夹杂片状石墨和孔表面覆盖Ni微粒的双损耗轻质吸波材料。当复合材料厚度为6.5 mm时,最小反射损耗为-35.01 dB,有效吸收带宽达到1.75 GHz。片状Al_(2)O_(3)锁定的石墨片构筑的导电网络,Ni微粒与基体之间的极化效应等共同促进复合材料良好的微波吸收性能。

Based on the high strength of flake Al_(2)O_(3) ceramic interlocking structure,Al_(2)O_(3) porous ceramics with high porosity and graphite were prepared,and Ni particles were prepared by in-situ reduction in the porous skeleton to form a lightweight double-loss ceramic-based absorbing material.The effects of reduction temperature on the composition,microstructure,element distribution and microwave absorption properties of porous absorbing materials were studied by XRD,FE-SEM and EDS.Results concluded the following.The results show that Ni on the framework can be completely reduced when the temperatures is up to 700℃.The composite with a double loss function is composed of an interlocking Al_(2)O_(3) matrix with graphite flakes embedded in it and Ni particles on the surface of pores.As the thickness of the composite is 6.5 mm,the reflection loss(RLmin)value is 35.01 dB and the effective bandwidth(RL≤10 dB)is 1.75 GHz.Microwave absorption can be attributed to the conductive network formed by graphite flakes between flaky Al_(2)O_(3) grains,as well as to the good impedance matching and polarization effect caused by the Ni particle-matrix interface.