填料法制备SiC_f/SiC复合材料的力学性能和高温介电性能  

Mechanical and High-temperature Dielectric Properties of SiC_f/SiC Composites with SiO_2 Filler

作　　者：穆阳 邓佳欣[1] 李皓[1] 周万城[2] MU Yang;DENG Jiaxin;LI Hao;ZHOU Wancheng(Department of Avionics, Chinese Flight Test Establishment, Xi＇an 710089,China;State Key Laboratory of SolidificationProcessing, Northwestern Polytechnical University, Xi＇an 710072, China)

机构地区：[1]中国飞行试验研究院航电所,西安阎良710089 [2]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《航空材料学报》2018年第3期31-39,共9页Journal of Aeronautical Materials

摘　　要：为获得性能优异的耐高温结构吸波材料,以纳米SiO_2颗粒为填料,采用有机先驱体浸渍裂解法(precursor infiltration and pyrolysis,PIP)制备SiC_f/SiC复合材料,研究填料对复合材料力学性能和高温介电性能的影响。结果表明:随着SiO_2含量从3%(质量分数,下同)增加至15%,SiC_f/SiC复合材料的弯曲强度先增加后减小,最高可达275 MPa;低介电常数SiO_2填料的引入使得复合材料的复介电常数逐渐减小,室温吸波性能得到有效改善,15%SiO_2含量的复合材料厚度为3.2~4.0 mm时,室温反射率在整个X波段均达到–8 d B以下;复合材料的复介电常数随着温度的升高逐渐增大,而SiO_2能显著降低高温复介电常数及其增幅,700℃时15%SiO_2含量复合材料在2.7~3.0 mm厚度范围具有优异的吸波性能。The mechanical and high-temperature dielectric properties of SiCf/SiC composites with nano-SiO2 filler were investigated in the present work for the development of high-temperature structural microwave absorbing materials. The results reveal that the flexural strength of SiCf/SiC composites is increased firstly and then is degraded with the filler content increased from 3% to 15%, and the maximum strength can be up to 275 MPa, meanwhile all of which show favourable fracture toughness. Owing to the high specific surface area and low permittivity of SiO2 filler, the complex permittivity of the composites decreases and the roomtemperature reflection loss （RL） is promoted with the increase of filler content. When the composites possess 15% SiO2 filler, the room-temperature RL values can be reached to –8 dB in the whole X band with the thickness of 3.2-4.0 mm. The complex permittivity of the composites increases with the rising temperatures, while the specific values and increasing range of the hightemperature complex permittivity can be significantly reduced by introducing the SiO2 filler, and the composites can obtain excellent microwave absorbing property at 700 ℃ with the thickness range of 2.7-3.0 mm.

关 键 词：SICF/SIC 复合材料 PIP 法 SiO2 填料 力学性能 高温介电性能 

分 类 号：TB34[一般工业技术—材料科学与工程]