Journal of Inorganic Materials ›› 2018, Vol. 33 ›› Issue (4): 427-433.doi: 10.15541/jim20170220

• Orginal Article • Previous Articles     Next Articles

Comparison of High-temperature Dielectric and Microwave Absorbing Property of Two Continuous SiC Fibers

Yang MU1(), Jia-Xin DENG1, Hao LI1, Wan-Cheng ZHOU2   

  1. 1. Department of Avionics, Chinese flight Test Establishment, Xi’an 710089, China;
    2. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China;
  • Received:2017-05-04 Revised:2017-06-23 Online:2018-04-30 Published:2018-03-27
  • About author:MU Yang. E-mail: 753340357@qq.com
  • Supported by:
    National Natural Science Foundation of China (51502236);Postdoctoral Science Foundation of China (2016M602940XB)

Abstract:

Two kinds of SiC fibers with different microstructures were analyzed by XPS, XRD and Raman spectra. The electrical conductivities of the fibers were measured, and their dielectric and microwave absorbing properties at elevated temperatures were investigated. Research results show that KD-I SiC fiber with rich carbon layers possess higher complex permittivities and electrical conductivities than do SLF SiC fiber with Si-C-O phase, resulting in poor impedance match between free space and KD-I fibers. Simultaneously, due to poor dielectric loss of SLF fiber, two fibers display inferior absorbing performance with the reflection loss values of -3.2 dB and -0.3 dB at X band, respectively. With temperatures increasing, ε° and ε? of KD-I fiber sharply increase, while the complex permittivity of SLF fiber display a small increment. Complex permittivities of two fibers are up to 20.9-j25.0 and 5.0-j0.37 at 700℃. Microwave absorbing properties of two fibers degrade at elevated temperatures, mainly ascribed to deterioration of impedance match.

Key words: SiC fibers, microstructure, electrical conductivity, high-temperature dielectric property, high- temperature microwave absorbing property

CLC Number: 

  • TB34