Study On Preparation And Microwave Absorption Performance Of SiC Whisker Obtained From Hydrogen Silicone Oil

Silicon carbide（SiC）whiskers have attracted much attention in the field of high temperature microwave absorption materials.Most of the methods for preparing SiC whiskers have problems such as complex processes,expensive costs,pollution or uneven morphology,which limit the application of SiC whiskers.Using hydrogen silicone oil as a raw material,SiC whiskers are grown on a carbon matrix through polymer-derived ceramics and simple chemical vapor deposition.The morphology,phase composition,microstructure and microwave absorption properties of SiC whiskers are discussed.The results show that the stacking fault density of the SiC whisker decreases and the ratio of length-diameter increases with the increase of the heat treatment temperature.The matrix has a significant effect on the morphology of SiC whiskers,and the morphology of the whiskers grown on the 2 mm graphite plate is good.Too large or too small particle size is detrimental to the growth of whiskers,and when a precursor with150～180μm is used,the grown SiC whiskers are hexagonal prisms.The microwave absorption performance of single SiC whisker is very poor,and the lowest reflection loss rate is-10.89 d B.The lowest reflection loss of SiC_w/SiC_f composite material made of PAN-based carbon fiber is-29.75 d B,and the effective bandwidth is 2.25GHz.The real and imaginary parts of the permittivity of SiC/Si₃N₄ composites are significantly reduced,which can be used as matching layer for microwave absorption materials.The SiC_w/Co composite material was prepared by electroless plating.When the electroless plating time is 15min,the lowest reflection loss reached-40.04 d B at 6.51 GHz.Carry out the construction of double-layer absorbing materials,and calculate the microwave absorption performance of the double-layer materials.The results show that the three kinds of double-layer absorbing materials can effectively reduce the reflection loss and widen the absorption band.By adjusting the type and thickness of the matching layer,the minimum reflection loss of the double-layer absorbing material obtained is-46.37 d B,and the maximum effective absorption bandwidth is 8.19 GHz.Figure 41;Table 5;Reference 91...