Effect of different kinds of SiC fibers on microwave absorption and mechanical properties of SiCf/SiC composites

Zhaowen Ren,Yingying Zhou,Yuchang Qing,Qinlong Wen,Wancheng Zhou,Yanyu Li,Shichang Duan

doi:10.1007/s10854-020-04129-5

Abstract

The SiC fibers are essential for designing microwave absorption and mechanical properties of multifunctional composites. In this study, SiCf/SiC composites were fabricated by SLF, KD-II, and KD-S SiC fibers. The SLF fibers are composed by amorphous SiOC. The KD-II and KD-S fibers reveal higher crystallizations. The conductivity of SLF, KD-II, and KD-S SiC fibers are 0.0127, 1.184, and 0.1316 S/cm, respectively. The flexural strength of SLF, KD-II, and KD-S SiCf/SiC composites are 147.77, 322.57, and 248.16 MPa, respectively. With the thickness of 2.3 mm, the microwave absorption property of SLF SiCf/SiC composites is over − 25 dB in X band. Additionally, the effective absorption bandwidth (EAB) of SLF SiCf/SiC composites below − 10 dB reaches 3.72 GHz with the thickness of 2.7 mm. In contrast, the KD-II SiCf/SiC composites only reach − 3.6 dB in X band when the thickness varies from 2 to 2.9 mm. With the thickness of 2 mm, the microwave absorption property of KD-S SiCf/SiC composites is over − 9 dB. With the thickness of 2.2 mm, the EAB of KD-S SiCf/SiC composites below − 7 dB reaches 4.12 GHz. The mechanisms of mechanical, microwave absorption, and penitential applications for SiCf/SiC composites are also discussed.

Highlights

Nowadays, as the development of microwave technology, electromagnetic pollution usually appears in daily life
We systematically investigated the properties of SiC fibers and the effects of different SiC fibers on microwave absorption and mechanical properties of SiCf/SiC composites
The SiCf/SiC composites fabricated with SLF, KD-II and KD-S SiC fibers by precursor impregnation and pyrolysis (PIP) method have similar density and open porosity values

Summary

Introduction

As the development of microwave technology, electromagnetic pollution usually appears in daily life. Continuous fiber reinforced ceramics matrix composites (CFRCMCs) were believed to be the most prospective multifunctional composites due to their high mechanical strength, stability under high temperature, low densities and oxidation resistance properties[8,9,10]. SiC fiber reinforced SiC ceramic matrix composites can be promising candidates of multifunctional materials with microwave absorption and mechanical properties. The microwave absorption and mechanical properties of SiC CFRCMCs depend on complex permittivity, electrical conductivity and free carbon content of SiC fibers, as well as interphase and matrix. The oxygen content of the second generation is lower than 2 wt% with enhanced limit temperature of about 1300 °C. The SLF, KD-II and KD-S SiC fibers are all produced in China and represent first, second and third generation of SiC fibers, respectively. We systematically investigated the properties of SiC fibers and the effects of different SiC fibers on microwave absorption and mechanical properties of SiCf/SiC composites

Experimental

Microstructure of SiC fibers

Conclusion