石英纤维增强石英陶瓷基(SiO2f/SiO2)复合材料具有优异的抗热震耐烧蚀和透波性能,是重要的天线罩材料.但是SiO2多孔亲水性,使得SiO2f/SiO2复合材料天线罩极易吸潮,严重影响航天器微波通讯功能.甲基三乙氧基硅烷和硼酸通过溶胶凝胶法制备聚硼硅氧烷防潮涂料.实验发现,复合材料在聚硼硅氧烷树脂中浸渍3次得到的涂层防潮效果最佳,表面接触角为130.33°,在50℃、相对湿度96％的条件下72 h后的吸水率降到0.33％.随着浸渍次数的增加,复合材料的弯曲强度逐渐下降.%SiO2f/SiO2 composite materials have been used for the radome due to its excellent thermal shock resistance and microwave transmission.However,the porous and hydrophilic characteristics of SiO2 lead to the absorption of moisture,resulting in unstability of dielectric properties.In this paper,the polyborosiloxane coatings are prepared by using methyl triethoxysilane and boric acid as raw materials.Experimental results show that the optimal moisture resistance of SiO2f/SiO2 is obtained by 3-time dipping in the polyborosiloxane coatings.Its contact angle is as high as 130.33°,and the moisture absorption is reduced to 0.33％ under the conditions of 50 ℃ and 96％ for 72 h.Howover,the bending strength of the composite might decrease slightly if being dipped for more times.
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