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以石英纤维预制件和硅溶胶为原料,采用溶胶-凝胶法制备了SiO2f/SiO2复合材料,在此基础上用尿素法制备了SiO2f/SiO2-BN复合材料,并对其力学性能和介电性能进行了测试。结果表明,随着工艺循环次数的不断增加,复合材料的密度随之提高,但增长速度逐渐减慢。三次循环后,SiO2f/SiO2-BN复合材料密度达1.81 g/cm3,弯曲强度和模量分别为113.9 MPa和36.5 GPa,分别比SiO2f/SiO2复合材料提高了12.1%和76.3%;纤维和基体界面结合良好,材料断面出现了明显的纤维拔出现象,为韧性断裂;复合材料介电常数和损耗角正切值分别为3.32和0.004,介电性能优良。
SiO2f / SiO2 composites were prepared by sol-gel method using quartz fiber preform and silica sol as raw materials, and SiO2f / SiO2-BN composites were prepared by urea method. The mechanical properties and dielectric constant Performance was tested. The results show that as the number of process cycles increases, the density of the composites increases, but the growth rate slows down. After three cycles, the density of SiO2f / SiO2-BN composites was 1.81 g / cm3, the flexural strength and modulus were 113.9 MPa and 36.5 GPa, respectively, which were 12.1% and 76.3% higher than that of SiO2f / SiO2 composites respectively. With good combination, obvious fiber pullout occurred in the cross section of the material, which was ductile fracture. The dielectric constant and loss tangent of the composites were 3.32 and 0.004, respectively. The dielectric properties were excellent.