Owing to the polysiloxane (PSO) characteristic of cheap, healthy, available and low free carbon content, in this research the SiC_f/SiOC composites were manufactured by polymer infiltration and pyrolysis (PIP) method with various content of SiO₂ fillers. It can be concluded from the DSC-TGA and XRD analysis that SiOC ceramic was formed from PSO when pyrolysis temperature exceeded 800°C and after pyrolysis at 1000°C the PSO mainly composed by amorphous SiO₂. The effects of SiO₂ fillers on morphology of SiOC matrix, flexural strength, complex permittivity, and microwave absorption property of SiC_f/SiOC composites were investigated. The results indicated that the SiO₂ fillers can enhance the density and reduce the microcracks of matrix. Therefore, the maximum flexural strength 201.09 MPa can be obtained by adding 5g SiO₂ filler into PSO precursor solution. The complex permittivity and flexural strength of composites first increased when content of SiO₂ filler enhanced from 0 to 5g. Nevertheless, with the content of SiO₂ filler increased from 5g to 10g and 15g, the complex permittivity and flexural strength of composites decreased. In summary, the SiC_f/SiOC composites with 10g SiO₂ fillers not only possess the reflection loss as low as -26.02 dB and the effective absorption bandwidth (EAB) below -10dB up to 3.21 GHz at the thickness of 3.0 mm but also own the flexural strength of 171.71 MPa.

鉴于聚硅氧烷（PSO）具有便宜，健康，可得且游离碳含量低的特点，本研究采用聚合物渗透和热解（PIP）方法制备了具有不同含量的SiO ₂填料的SiC _f / SiOC复合材料。从DSC-TGA和XRD分析可以得出结论，当热解温度超过800℃时，由PSO形成SiOC陶瓷，而在1000℃下热解后，PSO主要由非晶态SiO ₂组成。研究了SiO ₂填料对SiC _f / SiOC复合材料的SiOC基体形态，弯曲强度，复介电常数和微波吸收性能的影响。结果表明SiO ₂填料可以提高密度并减少基体的微裂纹。因此，通过向PSO前体溶液中添加5 g SiO ₂填料，可以获得最大挠曲强度201.09 MPa 。当SiO ₂填料的含量从0g增加到5g时，复合材料的复介电常数和弯曲强度首先增加。然而，随着SiO ₂填料含量从5g增加到10g和15g，复合材料的复介电常数和弯曲强度降低。总之，具有10g SiO ₂的SiC _f / SiOC复合材料 在厚度为3.0 mm时，填料不仅具有低至-26.02 dB的反射损耗和低于3.2dB GHz的-10dB以下的有效吸收带宽（EAB），而且具有171.71 MPa的抗弯强度。