1 华南理工大学材料科学与工程学院，广州 510640
2 北方民族大学材料科学与工程学院，银川 750021
采用固相法合成了高近红外(NIR)反射金红石型钛镍黄色料，并以SiO2气凝胶为基体，制备一种网络状NIR反射金红石型钛镍黄/硅气凝胶复合色料，测定了其结构特征和呈色性能，并分析其NIR反射效应和隔热性能。结果表明，添加1% (质量分数)助烧剂NaF所固相合成的金红石型钛镍黄色料呈色性能(b*=54.24)和NIR反射性能优异；所制备的网络状金红石型钛镍黄/硅气凝胶复合色料具有良好呈色性能、低透过率、高NIR反射率(96.60%)和低导热系数[0.068 54 W/(m·K)]，表明其具有优异的隔热性能。此外，还探讨了该复合色料的制备机制和隔热机理。
色料 近红外反射 气凝胶 隔热 pigment near infrared reflectance silica aerogel thermal insulation
国防科技大学空天科学学院新型陶瓷纤维及其复合材料重点实验室, 长沙 410073
Al2O3-SiO2气凝胶是一种低密度、高比表面积、高孔隙率、低热导率的三维结构纳米多孔材料, 在航空航天、建筑保温、石油化工等领域具有广泛的应用前景, 是理想的高温隔热基体之一。但纯Al2O3-SiO2气凝胶力学性能和抑制高温辐射传热能力较弱, 限制了自身在隔热领域的应用。采用纤维作为增强体, 制备的Al2O3-SiO2气凝胶复合材料同时具有较好的力学和隔热性能, 是目前国内外高温隔热材料方向的研究热点之一。本文介绍了纤维增强Al2O3-SiO2气凝胶隔热复合材料的制备方法, 综述了目前国内外该材料的研究进展, 并对其未来发展趋势做了展望。
隔热复合材料 纤维增强 Al2O3-SiO2气凝胶 力学性能 隔热性能 thermal insulation composite fiber reinforcement alumina-silica aerogel mechanical property thermal insulation performance
Author Affiliations
Abstract
1 Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, Tongji University, Shanghai200092, China
2 School of Physics Science and Engineering, Tongji University, Shanghai200092, China
3 National Space Science Center, Chinese Academy of Sciences, Beijing100190, China
4 Hangzhou Dianzi University, Hangzhou310018, China
5 Hangzhou Regenovo Biotechnology Co., Ltd., Hangzhou310038, China
As an attractive collector medium for hypervelocity particles, combined with outstanding physical properties and suitable compositional characteristics, SiO2 aerogel has been deployed on outer space missions and laser shock-loaded collection experiments. In this paper, impact experiments were conducted to understand the penetration process of irregular grains, irregular Al2O3 grains with two different sizes and speeds (~110 μm@7 km/s, ~251 μm@2.3 km/s) at various density silica aerogels. By classifying the shapes of projectile residues and tracks, the morphology of tracks was analyzed. It was observed that there were several kinds of typical tracks in the penetration of irregular grains, accompanied by residues with the shapes of near-sphere, polyhedron, streamlined body wedge, and rotator. The rotational behavior was demonstrated by the final status of one flake projectile as direct evidence. In addition, there was no obvious relationship between the track length and experimental parameters, which may be caused by the uncertain interaction between aerogels and irregular particles. In addition, it confirmed the existence of fragmentation, melting situation by observing the shape of the impact entrance hole. At the same time, optical coherence tomography was used to observe the detail of tracks clearly, which provided a method to characterize the tracks nondestructively.
hypervelocity impact experiment irregular grains morphology silica aerogel High Power Laser Science and Engineering
2021, 9(2): 02000e14
中国科学院上海技术物理研究所,红外物理国家重点实验室,上海,200083
采用溶胶-凝胶工艺在常压下制备了SiO2气凝胶薄膜,并用傅里叶红外光谱仪(FTIR)、扫描电子显微镜(SEM)、椭偏光谱仪等表征了薄膜的结构和性能.研究结果表明,气凝胶薄膜的折射率低达1.067,对应孔洞率为87.7%,密度为0.269×103kg·m-3,热导率为0.020W·m-1·K-1(300K)时,介电常数为1.52.这些优异性能的获得,主要归因于酸/碱两步催化、溶剂替换以及胶粒表面硅烷化等三个过程.
SiO2气凝胶薄膜 常压 孔洞率 silica aerogel thin films ambient pressure porosity
