Abstract:
nano SiC fiber modified chopped carbon fiber (nano SiC
f-C
fd) was prepred by catalytic chemical vapor deposition using Methyltrichlorosilane (MTS) as the precursor. Afterwards, nano SiC
f-C
fd/Si
3N
4 and C
fd/Si
3N
4 composites were manufactured by two-steps process, gelcasting and atmospheric sintering. The influence of nano SiC
f-C
fd and C
fd on dielectric response and microwave absorption properties within X-band(8.2-12.4 GHz) was studied by using network analyzer. The results show that the complex dielectric constant and dielectric loss tangent (tan δ)of two composites increase with the added amount of fiber. At the same fiber content, the real part of the dielectric constant of nano SiC
f-C
fd/Si
3N
4 composite is lower than that of C
fd/Si
3N
4 composites, but tan δ increases. Additionally, the results of calculated reflectivity show that nano SiC
f-C
fd/Si
3N
4 composites have strong microwave absorption. When the content of nano SiC
f-C
fd is 2wt% and the thickness is 2.5 mm, the maximum absorption peak can reach -14.95 dB. Moreover, the bandwidth of reflectivity (less than -5 dB) is up to 3.5 GHz. Therefore, nano SiC
f modification can effectively improve the microwave absorption property of C
fd/Si
3N
4 composites.
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