Microwave Absorbing Properties of Carbon Fibers Modified with BN/SiC Composite Coatings

doi:10.15541/jim20140014

Abstract

Abstract:

BN coating were prepared firstly on carbon fibers by dip-coating process using boric acid and urea as raw materials. Then, SiC coating were deposited on BN coating surface by chemical vapor deposition process using methyltrichlorosilane as precursor. Finally, BN/SiC composite coatings modified carbon fibers were obtained. The oxidation resistance, dielectric and microwave absorption properties, and microstructure of the BN/SiC composite coatings modified carbon fibers were investigated. The results showed that the thickness of the BN and SiC coating on the surface of carbon fibers were about 0.1 μm and 0.7 μm, respectively. After being modified by BN/SiC composite coatings, the initial and final oxidation temperatures of the modified carbon fibers were increased from 560℃ and 780℃ to 790℃ and above 1200℃, respectively. The dielectric properties of the modified carbon fibers changed significantly, and the microwave absorption properties were improved. Compared with the uncoated carbon fibers, the lowest reflectivity of the BN/SiC composite coatings modified carbon fibers with the thickness of 2 mm reduced to -13.3 dB, and the bandwidth (less than -10 dB) increased to 2.5 GHz.

Key words: BN/SiC composite coatings, carbon fibers, oxidation resistance, dielectric properties, microwave absorption properties

CLC Number:

TM25

ZHOU Wei, XIAO Peng, LI Yang, LUO Heng, HONG Wen. Microwave Absorbing Properties of Carbon Fibers Modified with BN/SiC Composite Coatings[J]. Journal of Inorganic Materials, 2014, 29(10): 1093-1098.

Figures/Tables 7

Fig. 1 XRD patterns of carbon fibers before and after modification (a) Carbon fibers, (b) BN modified carbon fibers and (c) BN/SiC composite coatings modified carbon fibers

Fig. 2 IR spectra of carbon fibers before and after modification (a) Carbon fibers, (b) BN modified carbon fibers and (c) BN/SiC composite coatings modified carbon fibers

Fig. 3 SEM images of carbon fibers before and after modification (a) Carbon fibers, (b) BN modified carbon fibers, (c) BN/SiC composite coatings modified carbon fibers. Inset shows the morphology of SiC coating

Fig. 4 TGA curves of carbon fibers before and after modification (a) Carbon fibers, (b) BN modified carbon fibers and (c) BN/SiC composite coatings modified carbon fibers

Fig. 5 Permittivity of non(Cf)-, BN- and BN/SiC-coating modified carbon fibers

Fig. 6 Illustrations of electron transport (a) Contact carbon fibers; (b) Carbon fibers conductinve network; (c) Contact BN/SiC composite coatings modified carbon fibers

Fig. 7 Microwave reflection loss of the carbon fibers (Cf) and coating modified carbon fibers

References 23

[1]	SINGH A P, GUPTA B K, MISHRA M, et al. Multiwalled carbon nanotube/cement composites with exceptional electromagnetic interference shielding properties. Carbon, 2013, 56: 86-96.
[2]	CHUNG D D L. Carbon materials for structural self-sensing, electromagnetic shielding and thermal interfacing. Carbon, 2012, 50(9): 3342-3353.
[3]	SINGH V K, SHUKLA A, PATRA M K, et al. Microwave absorbing properties of a thermally reduced graphene oxide/nitrile butadiene rubber composite. Carbon, 2012, 50(6): 2202-2208.
[4]	AL-SALEH M H, SUNDARARAJ U. Electromagnetic interference shielding mechanisms of CNT/polymer composites. Carbon, 2009, 47(7): 1738-1746.
[5]	IM J S, KIM J G, LEE Y S. Fluorination effects of carbon black additives for electrical properties and EMI shielding efficiency by improved dispersion and adhesion. Carbon, 2009, 47(11): 2640-2647.
[6]	CAO MAO-SHENG, SONG WEI-LI, HOU ZHI-LING, et al. The effects of temperature and frequency on the dielectric properties, electromagnetic interference shielding and microwave-absorption of short carbon fiber/silica composites. Carbon, 2010, 48(3): 788-796.
[7]	ROSA I M D, DINESCU A, SARASINI F, et al. Effect of short carbon fibers and MWCNTs on microwave absorbing properties of polyester composites containing nickel-coated carbon fibers. Compos. Sci .Technol., 2010, 70(1): 102-109.
[8]	XIE WEI, CHENG HAI-FENG, CHU ZENG-YONG, et al. Microwave absorbing properties of short hollow carbon fiber composites. Journal of Inorganic Materials, 2008, 23(3): 481-485.
[9]	LIU Y, ZHANG Z, XIAO S, et al. Preparation and properties of cobalt oxides coated carbon fibers as microwave-absorbing materials. Appl. Surf. Sci., 2011, 257(17): 7678-7683.
[10]	QIANG C, XU J, ZHANG Z, et al. Magnetic properties and microwave absorption properties of carbon fibers coated by Fe3O4 nanoparticles. J. Alloys Compd., 2010, 506(1): 93-97.
[11]	ZENG J, FAN H, WANG Y, et al. Oxidized electroplating zinc-covered carbon fibers as microwave absorption materials. J. Alloys Compd., 2012, 524: 59-62.
[12]	LIU YUAN, LIU XIANG-XUAN, CHEN XIN, et al. Preparation by MOCVD and microwave absorbing properties of CF@Fe. Journal of Inorganic Materials, 2013, 28(12): 1328-1332.
[13]	LI Z, ZHOU W, LUO F, et al. Improving the dielectric properties of SiC powder through nitrogen doping. Materials Science and Engineering: B, 2011, 176(12): 942-944.
[14]	LIU X, ZHANG Z, WU Y. Absorption properties of carbon black/silicon carbide microwave absorbers. Composites Part B: Engineering, 2011, 42(2): 326-329.
[15]	ZHAO D L, LUO F, ZHOU W C. Microwave absorbing property and complex permittivity of nano SiC particles doped with nitrogen. J. Alloys Compd., 2010, 490(1/2): 190-194.
[16]	WEN G, WU G L, LEI T Q, et al. Co-enhanced SiO2-BN ceramics for high-temperature dielectric applications. J. Eur. Ceram. Soc., 2000, 20(12): 1923-1928.
[17]	COFER C G, ECONOMY J. Oxidative and hydrolytic stability of boron nitride — A new approach to improving the oxidation resistance of carbonaceous structures. Carbon, 1995, 33(4): 389-395.
[18]	ZHANG X, DENG J, WANG L, et al. Phase transformation in BN films by nitrogen-protected annealing at atmospheric pressure. Appl. Surf. Sci., 2008, 254(21): 7109-7113.
[19]	HUANG Q, GU M, SUN K, et al. Effect of pretreatment on rheological properties of silicon carbide aqueous suspension. Ceram. Int., 2002, 28(7): 747-754.
[20]	DAS M, BASU A K, GHATAK S, et al. Carbothermal synthesis of boron nitride coating on PAN carbon fiber. J. Eur. Ceram. Soc., 2009, 29(10): 2129-2134.
[21]	VINOY K J, JHA R M. Radar Absorbing Materials: From Theory to Design and Characterization. Dordrecht, The Netherlands: Kluwer Academic Publishers, 1996.
[22]	SUMFLETH J, PREHN K, WICHMANN M H G, et al. A comparative study of the electrical and mechanical properties of epoxy nanocomposites reinforced by CVD- and arc-grown multi-wall carbon nanotubes. Compos. Sci. Technol., 2010, 70(1): 173-180.
[23]	CHEN Y J, CAO M S, WANG T H, et al. Microwave absorption properties of the ZnO nanowire-polyester composites. Appl. Phys. Lett., 2004, 84(17): 3367-3369.