Liquid metal technology of synthesis of ALOOH anisotropic nanostructured aerogel
New method for production of aerogel nanostructures (for example, AlOOH aerogel) with involvement of liquid metals is examined. In contrast with conventional sol-gel method for producing aerogels the role performed by the alcohol (aqueous) solution is played in the new method by liquid metal in which the base of the future aerogel structure dissociates and assembling of the nanostructure takes place within the gas phase covering the liquid metal. The latter obstacle fundamentally distinguishes the liquid metal method from the conventional technology of aerogel synthesis. Assembling of aerogel structure in the sol-gel method takes place as the result of removal of liquid phase at supercritical parameters which ultimately determines the value of the products. In the liquid-metal method there is no need to remove the liquid phase, because assembling of fractal nanostructure occurs in the gas phase. Liquid-metal aerogel production method is realized at low (usually atmospheric) pressure without the need to use of hazardous and corrosive reagents, and the heat released in the reaction is sufficient for maintaining the desired synthesis temperature. Results of studies of synthesis and properties of ultraporous aluminum oxyhydroxide Al2O3⋅n(H2O) (AlOOH aerogel) produced using the method of selective oxidation of Ga-Al and Bi-Al binary liquid metal fusions by water steam are presented in the preset paper. Studies of aerogel properties were performed using methods of scanning electron microscopy (SEM), X-ray diffraction (XRD), synchronous differential scanning calorimetry and thermogravimetry (DSC/TG), as well as by energy dispersive X-ray (EDX) spectroscopy. It was established on the basis microstructure analysis that the aerogel has space-oriented fibrous nanostructure with «tensile» type anisotropy and fiber diameters varying from 5 to 15 nm. It follows from XRD studies that AlOOH aerogel remains to be amorphous up to 1000°С. Results of studies of thermal physical properties of the aerogel and its elemental composition are presented. It was established that aerogel has low thermal conductivity (~ 0.01 – 0.03 W/(m⋅K)) within rather wide temperature range from 130 to 1300 K.
- Baker J. Look into the Seeds of Time. Science. 2006, v. 314, p. 1707.
- Brownlee D. Comet 81P/Wild 2 under a microscope. Science. 2006, v. 314, p. 1711.
- Miller J.B., Rankin S.E., Ko E.I. Strategies in controlling the homogeneity of zirconia-silica aerogels: effect of preparation on textural and catalytic properties. Journal of Catalysis. 1994, v. 148, p. 673.
- Ivanov I.I., Shelemetiev V.M., Ulyanov V.V., Teplyakov Yu.A. Kinetics of the reduction of orthorhombic and tetragonal lead oxides with hydrogen. Kinetics and catalysis. 2015, v. 56, no. 3, pp. 305-309 (in Russian).
- Friske J., Emmerling A. Aerogels – Preparation, properties, applications. Structure and Bonding. 1992, v. 77, pp. 37-87.
- Gulevich A.V., Martynov P.N., Gulevsky V.A., Ulyanov V.V. Technologies for hydrogen production based on direct contact of gaseous hydrocarbons and evaporated water with molten Pb and Pb-Bi. Energy conversion and management. 2008, v. 49, no. 7, pp. 1946-1950.
- Poelz G., Riethmuller R. Preparation of silica aerosol for Cherenkov counters. Nuclear Instruments and Methods. 1982, v. 195, p. 491.
- Hrubesh L.W., Tillotson T.M., Poco J.F. in: Zelinski B.J.J., Brinker C.J., Clark D.E., Ulrich D.R. (Eds.). Better Ceramics Through Chemistry IV, MRS Symposia Proceedings No. 180, Materials Research Society. Pittsburgh, 1990, p. 315.
- Askhadullin R.Sh., Martynov P.N., Yudintsev P.A., Osipov A.A., Simakov A.A., Chaban A.Yu., Matchula E.A. Liquid metal based technology of synthesis of nanostructured materials (by the example of oxides). The materials properties and applications areas. Journal of Physics: Conference Series. 2008, v. 98.
- Orlov Y.I., Efanov A.D., Martynov P.N., Gulevsky V.A., Papovyants A.K., Levchenko Yu.D., Ulyanov V.V. Hydrodynamic problems of heavy liquid metal coolants technology in loop-type and mono-block-type reactor installations. Nuclear engineering and design. 2007, v. 237, no. 15-17, pp. 1829-1837.
- Chan M., Mulders N., Reppy J. Helium in aerogel. Physics Today. 1996, v. 49, no. 8, pp. 30-38.
- Porto J.V., Parpia J.M. Superfluid 3He in aerogel. Physical Review Letters. 1995, v. 74, no. 23, pp. 4667-4670.
- Dmitriev V.V., Askhadullin R.Sh., Martynov P.N., Osipov A.A., Krasnikhin D.A., Senin A.A., Yudin A.N. Phase diagram of superfluid 3 He in «nematically order» aerogel. JETP Letters. 2012, v.95, no. 6, pp. 355-360.
- Dmitriev V.V., Askhadullin R.Sh., Martynov P.N., Osipov A.A., Senin A.A., Yudin A.N. Anisotropic 2D Larkin-Imry-Ma state in polar distorted ABM phase of 3He in «nematically order» aerogel. JETP Letters. 2014, v.100, no. 10. Available at: http://arxiv.org/abs/1410.5194.
- Dmitriev V.V., Senin A.A., Soldatov A.A., Yudin A.N. Polar phase of superfluid 3He in anisotropic aerogel. Available at: http://arxiv.org/abs/1507.04275.
- Teichner S.J. in: J. Fricke (Ed.), Aerogels: Proceedings of the First International Symposium, Wurzburg, Fed. Rep. of Germany, September 23-25, 1985, Springer, Berlin, New York, 1985, p. 22.
- Kistler S.S. Coherent expanded aerogels and jellies. Nature. 1931, v. 127, no. 3211, p. 741.
- Teichner S.J., Nicoloan G.A. Method of preparing inorganic aerogels. Colloid and Interphase Science. 1976, v. 5, no. 3, pp. 245-273.
- Astier M., Bertrand A., Bianchi D., Chenard A., Gardes G.E.E., Pajonk G., Taghavi M.B., Teichner S.J., Villemin B. Preparation of catalyst. Eds. B. Delmon et.al. Amsterdam. Elsevier, 1976, 315 p.
- Schmidt H. Chemistry of material preparation by the sol-gel process. Journal of Non-Crystalline Solids. 1988, v. 100, pp. 51-64.
- Woignier T., Phalippou J., Zarzucki J. Monolithic aerogels in the systems SiO2-B2O3, SiO2-P2O5, SiO2-B2O3-P2O5. Journal of Non-Crystalline Solids. 1984, v. 63, pp. 117-130.
- Husing N., Schubert U. Aerogele – luftige Materialien: Chemie, Struktur und Eigenschaften. Angew. Chem. 1998, v. 110, pp. 22-47.
- Asadchikov V.E., Askhadullin R.Sh., Volkov V.V., Dmitriev V.V., Kitaeva N.K., Martynov P.N., Osipov A.A., Senin A.A., Soldatov A.A., Chekrigina D.I., Yudin A.N. Structure and properties of «nematically oriented» aerogels. Pisma v ZhETPh. 2015, v. 101, no. 8, pp. 613-619 (in Russian).