摘要
前驱体转化SiBCN气凝胶具有独特的孔隙结构、低的热导率和优异的高温性能,是一种理想的超高温隔热材料,但是其在高温使用过程中容易发生析晶和分解反应,引起多孔结构的破坏和性能的恶化等问题.以聚硼硅氮烷为前驱体,湿化学法合成的(Zr,Hf)C前驱体为金属源,二乙烯基苯为交联剂和碳源,通过溶剂热反应、冷冻干燥、高温热解和热处理等步骤制备出(Zr,Hf)C/SiBCN复合气凝胶.这种复合气凝胶具有典型的珍珠项链状三维多孔结构,比表面积达到74.33 m^(2)/g,孔径约为20 nm,介孔结构是在溶剂热过程中通过凝胶化反应形成的.X射线衍射分析表明,(Zr,Hf)C相是由(Zr,Hf)C前驱体与体系中的高活性自由碳通过碳热还原反应形成的.本研究为多元金属共改性SiBCN复合气凝胶的制备提供了新的思路和技术支持.
Precursor-derived SiBCN aerogel is an ideal ultra-high-temperature insulation material due to its unique pore structure,low thermal conductivity and excellent thermal stability.However,it is prone to occur crystallization and decomposition reactions under high-temperature environments,resulting in destruction of porous structure and deterioration of performance.In this work,a(Zr,Hf)C/SiBCN hybrid aerogel was prepared by solvothermal reaction,freeze-drying,pyrolysis and thermal treatment using polyborosilazane as precursor,(Zr,Hf)C precursor synthesized by wet chemical method as metal source,divinylbenzene as crosslinking agent and carbon source.The(Zr,Hf)C/SiBCN hybrid aerogel possesses a typical pearl necklace-like porous structure with a specific surface area of 74.33 m^(2)/g and the pore size of~20 nm,and these mesopores are formed by gelation reaction during solvothermal process.X-ray diffraction analysis shows that the(Zr,Hf)C phase is formed by the carbothermal reduction reaction between the(Zr,Hf)C precursor and the highly active free carbon in the system.This work provides new route and technical support for the preparation of multi-metal elements modified SiBCN-based aerogels.
作者
呼子峰
王婉怡
鲁铭心
苏冬
HU Zi-feng;WANG Wan-yi;LU Ming-xin;SU Dong(School of Materials Science and Engineering,Tianjin University,Tianjin 300350,China)
出处
《高分子通报》
北大核心
2025年第7期1117-1123,共7页
Polymer Bulletin
基金
国家自然科学基金(基金号52173261)
先进功能复合材料技术重点实验室基金(基金号6142906240505)。
