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Influence of Ti addition on boehmite-derived aluminum silicate aerogels: structure and properties |
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| Authors: | Frances I Hurwitz Haiquan Guo Richard B Rogers Erik J Sheets Derek R Miller Katy N Newlin Molly K Shave Anna R Palczer Michael T Cox |
| Institution: | 1. NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, OH, 44135, USA 2. Ohio Aerospace Institute, Cleveland, OH, USA 3. Purdue University, West Lafayette, IN, USA 4. Michigan State University, East Lansing, MI, USA 5. Univesity of Louisville, Louisville, KY, USA 6. Colorado School of Mines, Golden, CO, USA 7. Arctic Slope Regional Corporation, Cleveland, OH, USA |
| Abstract: | Aluminosilicate aerogels offer potential for extremely low thermal conductivities at temperatures greater than 900?°C, beyond where silica aerogels reach their upper temperature use limits. Aerogels have been synthesized at two Al:Si ratios, a 3Al:1Si mullite composition, and an 8Al:1Si alumina rich composition. Boehmite (AlOOH) is used as the Al source, and tetraethoxysilane as the Si precursor. The influence of Ti as a ternary constituent, introduced through the addition of titanium isopropoxide in the sol?Cgel synthesis, on aerogel morphology and thermal properties is evaluated. Four different boehmite precursor powders are evaluated. Morphology, surface area and pore size, and thermal transformation vary with the crystallite size of the starting boehmite powder, as does incorporation of titanium and evolution of Ti-containing crystalline phases. The addition of Ti influences sol viscosity, gelation time, surface area and pore size distribution, as well as phase formation on heat treatment. |
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