BN/SiC复合涂层改性炭纤维的吸波性能研究

doi:10.15541/jim20140014

摘要/Abstract

摘要：

以尿素、硼酸为原料, 采用浸涂工艺先在炭纤维表面制备BN涂层, 再以三氯甲基硅烷为前驱体, 采用化学气相沉积工艺在纤维表面沉积SiC涂层, 制得了BN/SiC复合涂层改性炭纤维。对BN/SiC复合涂层改性炭纤维的微观结构、抗氧化性能、介电性能及吸波性能进行了研究。结果表明: 炭纤维表面BN涂层的厚度约为0.1 μm, SiC涂层的厚度约为0.7 μm。炭纤维经表面BN/SiC复合涂层改性后, 抗氧化性能明显提高, 开始明显氧化失重温度从560℃提高到790℃, 最终氧化温度从780℃提高到1200℃以上; 且介电性能得到有效改善, 吸波性能显著提高。相比于未改性炭纤维, 厚度为2 mm的BN/SiC复合涂层改性炭纤维的最小反射率减小到-13.3 dB, 小于-10 dB的带宽增加至2.5 GHz。

关键词: BN/SiC复合涂层, 炭纤维, 抗氧化性能, 介电性能, 吸波性能

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

中图分类号:

TM25

周伟, 肖鹏, 李杨, 罗衡, 洪文. BN/SiC复合涂层改性炭纤维的吸波性能研究[J]. 无机材料学报, 2014, 29(10): 1093-1098.

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.

图/表 7

图1 炭纤维改性前后的XRD图谱

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

图2 炭纤维改性前后的红外光谱

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

图3 炭纤维改性前后的SEM照片

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

图4 炭纤维和涂层改性炭纤维的TGA氧化曲线

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

图5 炭纤维和涂层改性炭纤维的复介电常数

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

图6 炭纤维中电子运动示意图

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

图7 炭纤维和涂层改性炭纤维的反射率曲线

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

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