轻质高强硅氧碳气凝胶的制备及其高温隔热性能  

Preparation of Lightweight and High-Strength Silicon Oxycarbide Aerogels and Their Thermal Insulation Performance

作　　者：祝文霞 王昊 季惠明[1] 苏冬 ZHU Wenxia;WANG Hao;JI Huiming;SU Dong(School of Materials Science and Engineering,Tianjin University,Tianjin 300350,China)

机构地区：[1]天津大学材料科学与工程学院,天津300350

出　　处：《硅酸盐学报》2024年第9期2773-2779,共7页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(52173261);天津市自然科学基金(19JCYBJC18200)。

摘　　要：陶瓷气凝胶因其优异的隔热性能和高温稳定性而成为新型的高性能热防护材料,但是低的强度限制了其应用和发展。本工作以聚甲基氢硅氧烷作为前驱体、四乙烯基环四硅氧烷为交联剂,通过水热反应和冷冻成型,再经热解过程制备出轻质高强、耐高温的硅氧碳(SiOC)陶瓷气凝胶。多孔的蜂窝结构赋予SiOC气凝胶低的密度(0.13 g·cm^(-3))和热导率(0.0655 W·m^(-1)·K^(-1))以及高的抗压强度(0.96 MPa)。同时,SiOC气凝胶表现出优异的高温稳定性,在1400℃热处理和800℃氧化处理后未出现结构的坍塌,热导率和抗压强度基本保持不变。Introduction With the rapid development of high-technology fields,advanced aerogel acts as the thermal insulation materials under high-temperature environment attracted extensive attention.Polymer derived ceramic(PDC)aerogels were considered to be a promising thermal protection materials due to its low density,high porosity,excellent thermal insulation performance and high-temperature stability.Silicon oxycarbide(SiOC)ceramic aerogels,one kind of typical representative PDC materials,were mainly formed by partial substitution of C atoms for O atoms in SiO_(2)tetrahedra.Compared the traditional silica aerogels,silicon oxycarbide(SiOC)aerogels exhibited better thermal and chemical stability as well as higher mechanical strength.Previously research reported that SiOC aerogels were mainly prepared by sol-gel method and PDC route,exhibited a higher density,which limited its applications and development in lightweight thermal insulation filed.Moreover,the obtained SiOC aerogels exhibited a necklace-like structure,poor high-temperature stability and mechanical strength due to the weak contact between nanoparticles.And most researches on SiOC aerogels focused on its high-temperature pyrolysis behavior.In this paper,a lightweight and high-strength SiOC aerogel were prepared using polyhydromethylsiloxane(PHMS)as precursor and tetramethyltetravinylcycletetrasiloxane(D_(4)Vi)as crosslinker through solvothermal,freeze casting and pyrolysis.The influence of D_(4)Vi content on the microstructure and thermal stability of SiOC aerogels were discussed.The evolution of phase composition,mechanical strength and thermal insulation performance was further explored via high-temperature heat treatment and oxidation treatment.Methods In a typical process,1.5 g D_(4)Vi and 1.0 g PHMS were added into 52.4 g cyclohexane solvent and mixed uniformly by magnetic stirring for 30 min.Then,1%Pt catalyst was added into the mixture for another 15 min stirring to obtain the transparent polysiloxane(PSO)solution.The PSO solution was then poured into a

关 键 词：硅氧碳陶瓷 隔热性能 高温稳定性 抗氧化性能 

分 类 号：TB322[一般工业技术—材料科学与工程]