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Abstract

This paper presents a laboratory study on synthesis and properties of ultraporous aluminum oxyhydroxide Al2O3n(H2O) (AlOOH aerogel) using a method of selective oxidation of Ga-Al and Bi-Al binary liquid metal fusions by water steam. Aerogel properties were studied by using the methods of scanning electron microscopy (SEM), X-ray diffraction (XRD), synchronous differential scanning calorimetry and thermogravimetry (DSC/TG), and energy dispersive X-ray (EDX) spectroscopy. The results of microstructure analysis showed that the aerogel had oriented in the space fibrous nanostructure with a “tensile” type of anisotropy, a fiber diameter varying from 5 to 15 nm. XRD examination showed that AlOOH aerogel kept amorphous up to 1000°. Results of the studies on thermal properties of the aerogel and its elemental composition are presented. It has been determined that aerogel has low thermal conductivity (~ 0.02-0.03 W/(mK) within a rather wide temperature range. Studies on using of small additives of AlO aerogel (0.5-5 max. %) to ceramic materials based on silicon nitride Si3N4, silicon carbide SiC, and zirconium dioxide ZrO2 showed that aerogel additive made it possible to increase physical and mechanical characteristics of ceramics in average on 20-30 %.