以聚硅氮烷为前驱体的Si-C-N陶瓷对雷达波的吸收应用

APPLICATION OF POLYSILAZANE-DERIVED Si-C-N CERAMICS IN RADAR ABSORPTION

氨解甲基氯硅烷和苯基氯硅烷单体可得到聚硅氮烷前驱体,其高温裂解和球磨后获得的Si-C-N陶瓷粉末能吸收X波段(8GHz～12GHz)的雷达波,其吸收性能随氯硅烷单体的配比不同而变化。当将Si-C-N陶瓷粉末与磁性材料复合后,吸收性能大为改进,厚度2.20mm的吸收层,面密度仅为2.86kg/m2,在10.47GHz处吸收可达-28.84dB,证明了阻抗匹配在研制雷达吸收材料方面的重要性,并提出Si-C-N陶瓷与μ′、μ″值更高的磁性材料复合,吸收性能将会得到更大的提高。

A composite comprising a magnetic material and Si-C-N ceramic powders yielded from the pyrolysis of polysilazane precursors could well absorb the X band (8 GHz^12 GHz) radar. When methylchlorosilanes and phenylchlorosilane were ammonolyzed with ammonia gas, various polysilazanes were produced which could be typically pyrolyzed at high temperature and subsequently ground into Si-C-N ceramic powders. It had been demonstrated that the attained ceramics could absorb radar at the range of 8 GHz to 12 GHz and that the absorption would vary with the ratios of chlorosilane monomers. Furthermore, when Si-C-N ceramic powders are composited with one magnaic material, the absorptive properties are greatly improved. For instance, if the absorbing layer is 2.20 mm thick, the surface density is only (2.86) kg/m^2 whereas the maximum absorption could be as great as (-28.44) dB at (10.47) GHz, showing the importance of impedance matching in the manufacture of radar-absorbing materials. It was also assumed that if magnetic materials with higher μ′, μ″ values are composited with Si-C-N ceramics, more effective radar absorbers would be obtained.