For the application requirement in aerospace and further expanding the application field of aerogel, the fabrication of gradient density aerogel SiO2 has been researched in this paper. By a self-built device, a continuously graded silica aerogel is fabricated via special sol-co-gelation techniques, with tetraethoxysilane (TEOS) as the organic precursor and by a supercritical drying process. Its density ranges from 60 mg/cm3 to 160 mg/cm3. Scan electron microscope, X-ray phase contrast method and optical microscopy are used to characterize the graded density silica aerogel prepared. Compared with the graded density silica aerogel produced by layer-by-layer gelation techniques, the sol-co-gelation techniques smooth out density mutation and increase the interdiffusion between adjacent layers, which makes density change tend to be more continuous. The gradient density aerogel fabricated by such a method expands greatly the application of conditional aerogel. It can potentially be used in many fields such as acoustic impedance matching and interstellar particles collection.
GUI Jiayin, ZHOU Bin, ZHONG Yanhong, DU Ai, SHEN Jun
. Fabrication of Graded Density SiO2 Aerogel via Sol-Co-Gelation Techniques[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2011
, 32(5)
: 941
-947
.
DOI: CNKI:11-1929/V.20101213.1757.012
[1] Zolensky M E, Zega T J, Yano H, et al. Mineralogy and petrology of comet 81P/Wild 2 nucleussamples[J]. Science, 2006, 314 (5806): 1735-1739.
[2] Sandford S A, Aleon J, Alexander C M, et al. Organics captured from comet 81P Wild 2 by the Stardust spacecraft[J]. Science, 2006, 314(5806): 1720-1724.
[3] Tsou P. Silica aerogel captures cosmic dust intact[J]. Journal of Non-Crystalline Solids, 1995, 186: 415-427.
[4] Tsou P, Brownlee D E, Sandford S A, et al. Wild 2 and interstellar sample collection and earth return[J]. Journal of Geophysical Research, 2003, 108(E10):8113-8133.
[5] Brownlee D E, Tsou P, Atkins K L, et al. Stardust: finessing expensive cemetery sample returns[J]. Acta Astronautica, 1996, 39 (1-4): 51-60.
[6] Jones S M. A method for producing gradient density aerogel[J]. Journal of Sol-Gel Science and Technology, 2007, 44(3): 255-258.
[7] Jones S M. Aerogel space exploration applications[J]. Journal of Sol-Gel Science and Technology, 2006, 40(2-3):351-357.
[8] Jones S M. Gradient composition sol-gel materials//Proceedings of SPIE. 2000, 3943: 260-269.
[9] Hrubesh L W, Alviso C T. Optical characterization of silica aerogel[J]. Materials Research Society, 1988, 121: 703-709.
[10] Gerlach R, Kraus O, Fricke J, et al. Modified SiO2 aerogels a acoustic impedance matching layers in ultrasonic devices[J]. Journal of Non-Crystalline Solids, 1992,145: 227-232.
[11] Bellunato T, Calvi M, Matteuzzi C, et al. Refractive index of silica aerogel: uniformity and dispersion law[J]. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2008,595(1): 183-186.
[12] Hüsing N, Schubert U. Aerogels—airy materials: chemistry, structure, and properties[J]. Angewandte Chemie International Edition, 1998, 37(1-2): 22-45.
[13] Burchell M J, Fairey S A J, Foster N J, et al. Hypervelocity capture of particles in aerogel: dependence on aerogel properties[J]. Planetary and Space Science, 2009,57(1): 58-70.
[14] Jones S M. Aerogel: space exploration applications[J]. Journal of Sol-Gel Science and Technology, 2006,40(2-3): 351-357.
[15] 禹爱民,李政,章迪,等. 微焦点X射线源类同轴相衬成像[J]. 高能物理与核物理,2006,30(11): 1119-1122. Yu Aimin,Li Zheng,Zhang Di,et al. In-line phase contrast imaging using a micro-focus X-ray source[J]. High Energy Physics and Nuclear Physics,2006,30(11): 1119-1122. (in Chinese)
CJA