| 引用本文: | 王衍飞,张长瑞,冯坚,等.SiO2气凝胶复合短切莫来石纤维多孔骨架复合材料的制备及性能.[J].国防科技大学学报,2008,30(6):24-28.[点击复制] |
| WANG Yanfei,ZHANG Changrui,FENG Jian,et al.Fabrication and Properties of SiO2-aerogel Loading Chopped Mullite Fiber Porous Skeleton Composite[J].Journal of National University of Defense Technology,2008,30(6):24-28[点击复制] |
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| SiO2气凝胶复合短切莫来石纤维多孔骨架复合材料的制备及性能 |
| 王衍飞, 张长瑞, 冯坚, 姜勇刚 |
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(国防科技大学 航天与材料工程学院，湖南 长沙 410073)
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| 摘要: |
| 将短切莫来石纤维、硅溶胶、B4C粉，经过1260℃烧结制备多孔骨架，以正硅酸乙酯、去离子水和乙醇配制SiO2溶胶，并将多孔骨架与SiO2溶胶浸渍，经过超临界干燥制备SiO2气凝胶复合的莫来石隔热瓦。通过热重和差热分析、X射线能谱分析，表明B4C在700℃～900℃时发生氧化，生成B2O3将短切纤维粘接到一起，莫来石多孔骨架在1500℃以下稳定存在。具有纳米级孔洞结构的SiO2气凝胶填充了多孔骨架的微米级孔洞，隔热瓦的热导率在200℃、500℃、800℃、1000℃分别下降了44.3%、33.8%、34.6%、29.5%。此外，SiO2气凝胶的复合使得抗弯和抗压强度分别提高了50%和40%。 |
| 关键词: 短切莫来石纤维 烧结助剂 SiO2气凝胶 纳米多孔 热导率 力学性能 |
| DOI： |
| 投稿日期：2008-05-23 |
| 基金项目:国家部委基金资助项目 |
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| Fabrication and Properties of SiO2-aerogel Loading Chopped Mullite Fiber Porous Skeleton Composite |
| WANG Yanfei, ZHANG Changrui, FENG Jian, JIANG Yonggang |
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(College of Aerospace and Materials Engineering, National Univ. of Defense Technology, Changsha 410073, China)
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| Abstract: |
| Chopped mullite fiber porous skeleton was sintered at 1260℃ by colloidal silica and B4C powders. Then Porous skeleton was loaded with silica-sols prepared by tetraethyloxylane(TEOS), deionized water and ethanol. Silica-aerogels loading chopped mullite fiber porous skeleton was achieved by supercritical drying. Via thermogravimetry(TG), differential thermal analysis(DTA) and energy dispersive spectrometry(EDS), it was revealed that at 700℃～900℃, B4C was oxidized into B2O3 which bound chopped fibers. Furthermore, chopped mullite fiber porous skeleton was chemically stable below 1500℃. Insulation tiles possessed nanoporous structure since silica-aerogels filled microporous pores of chopped mullite fiber skeleton. Thus thermal conductivity of insulation tiles was reduced by 44.3%, 33.8%, 34.6%, 29.5% at 300℃, 500℃, 800℃ and 1000℃ respectively. Besides, the loading of silica-aerogels improved flexural strength and compressive strength of porous skeleton at 50% and 40%, respectively. |
| Keywords: chopped mullite fiber agglomerating agent silica-aerogels nanoporous structure thermal conductivity mechanical properties |
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