Improved electromagnetic absorbing properties of Si3N4–SiC/SiO2 composite ceramics with multi-shell microstructure
Improved electromagnetic absorbing properties of Si3N4–SiC/SiO2 composite ceramics with multi-shell microstructure
复制标题
DOI：
10.1016/j.jeurceramsoc.2013.03.021
复制
发表时间：
2013-10
影响因子：
5.7
通讯作者：
G. Zheng;X. Yin;Shanhua Liu;Xingmin Liu;Juanli Deng;Quan Li
中科院分区：
文献类型：
--
作者：
G. Zheng;X. Yin;Shanhua Liu;Xingmin Liu;Juanli Deng;Quan Li
采用化学气相渗透法（CVI）在多孔β-Si 3 N4陶瓷上制备了SiC涂层，并在涂层中添加纳米晶，制备了多孔Si 3 N4-SiC复合陶瓷。在1100°C空气中氧化时，棒状Si 3 N4-SiC颗粒表面形成SiO2膜。制备的Si 3 N4-SiC/SiO2复合陶瓷具有多壳层结构，阻抗失配减小，吸波性能优异。在空气中氧化10 h制备的Si 3 N4-SiC/SiO2在8.7GHz处的反射损耗为− 30 dB（>99.9%吸收），样品厚度为3.8mm。当样品厚度为3.5mm时，在8.3-12.4GHz频率范围内，Si 3 N4-SiC/SiO2的反射损耗小于-10dB（>90%吸收），有效吸收带宽为4.1GHz。
Porous Si3N4–SiC composite ceramic was fabricated by infiltrating SiC coating with nano-scale crystals into porous β-Si3N4ceramic via chemical vapor infiltration (CVI). Silica (SiO2) film was formed on the surface of rod-like Si3N4–SiC grains during oxidation at 1100°C in air. The as-received Si3N4–SiC/SiO2composite ceramic attains a multi-shell microstructure, and exhibits reduced impedance mismatch, leading to excellent electromagnetic (EM) absorbing properties. The Si3N4–SiC/SiO2fabricated by oxidation of Si3N4–SiC for 10h in air can achieve a reflection loss of −30dB (>99.9% absorption) at 8.7GHz when the sample thickness is 3.8mm. When the sample thickness is 3.5mm, reflection loss of Si3N4–SiC/SiO2is lower than −10dB (>90% absorption) in the frequency range 8.3–12.4GHz, the effective absorption bandwidth is 4.1GHz.