High Temperature Hydrophobic Modification and Failure Mechanism of Silica Aerogel Thermal Insulation Composites

Abstract

Abstract: SiO₂ aerogel thermal insulation composites have been widely used in aerospace, petrochemical and other thermal insulation fields, and their application can be significantly expanded through hydrophobic modification. In order to maintain good hydrophobic properties of SiO₂ aerogel thermal insulation composites at high temperature, polysiloxane modified silicate coatings were used to modify the surface hydrophobicity of SiO₂ aerogel thermal insulation composites by brushing. The effect of coating thickness on crack expansion was then investigated, as well as the failure mechanism of hydrophobic properties of the coating at high temperature and the wear resistance of the composite before and after brushing coating modification. The results show that the surface of the coating is crack-free and the contact angle reaches (113±2)° when the coating thickness is about 13 μm. The contact angle still is maintained at 105° after heat treatment at 450 ℃ for 1 800 s, showing good thermal stability. Meanwhile, the coating significantly improves the wear resistance of composites.

Key words: SiO₂ aerogel thermal insulation composite, polysiloxane modified silicate, thermal resistance, hydrophobic modification, wear resistance, coating

CLC Number:

TB332

HE Hui, JIANG Yonggang, ZHANG Zhongming, FENG Junzong, LI Liangjun, FENG Jian. High Temperature Hydrophobic Modification and Failure Mechanism of Silica Aerogel Thermal Insulation Composites[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2022, 41(5): 1813-1820.

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