Study on Mullite Whiskers Preparation via Non-Hydrolytic Sol-Gel Process Combined with Molten Salt Method

Abstract:

Mullite whiskers were prepared via non-hydrolytic sol-gel process combined with molybdate molten salt using tetraethoxysilane and anhydrous aluminum chloride as precussor, anhydrous ether as oxygen donor, molybdate as molten salt. The effects of heat treatment temperature, molten salt amount, holding time on synthesis and morphology of mullite whiskers were investigated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The results show that the mullite whiskers appeared at the lowest temperature of 800°C, and optimized mullite whiskers could be prepared at 900°C for 8 h with the mass ratio of xerogel and molybdate as 1:2, the diameter of the whiskers was in the range of 0.15-0.22 μm with the aspect ratio of more than 40.

• Periodical: Materials Science Forum (Volume 848)
• Pages: 295-300
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.848.295
• Online since: March 2016
• Authors: Kai Lin Fu, Wei Hui Jiang, Jian Min Liu, Guo Feng, Mu Pan
• Keywords: Molten Salt Method, Molybdate, Mullite Whiskers, Non-Hydrolytic Sol-Gel

References

[1] C. Aksel, The role of fine alumina and mullite particles on the thermomechanical behaviour of alumina–mullite refractory materials, Mater. Lett. 57 (2002) 708-714.

DOI: 10.1016/s0167-577x(02)00858-3

[2] I.A. Aksay, J.A. Pask, The silica-alumina system: stable and metastable equilibria at 1. 0 atmosphere, Science. 183 (1974) 69-71.

DOI: 10.1126/science.183.4120.69

[3] J. Ossaka, Tetragonal mullite-like phase from co-precipitated gels, Nature. 191 (1961) 1000-1001.

DOI: 10.1038/1911000a0

[4] A.R. Guo, J.C. Liu, Y. Wang, H. Xu, Preparation of porous lamellar mullite ceramics with whisker skeletons by electrospinning and pressure molding, Mater. Lett. 74 (2012) 107-110.

DOI: 10.1016/j.matlet.2012.01.080

[5] B.M. Kim, Y.K. Cho, S.Y. Yoon, R. Stevens, H.C. Park, Mullite whiskers derived from kaolin, Ceram. Int. 35 (2009) 579-583.

DOI: 10.1016/j.ceramint.2008.01.017

[6] C. Duran, Y. K. Tur, Templated grain growth of textured mullite/zirconia composites, Mater. Lett., 59 (2005) 245-249.

DOI: 10.1016/j.matlet.2004.07.058

[7] M.F. Souza, J. Yamamoto, I. Regiani, Mullite whiskers grown from erbia-doped aluminum hydroxide-silica gel, J. Am. Ceram. Soc. 83 (2000) 60-64.

DOI: 10.1111/j.1151-2916.2000.tb01148.x

[8] H. Katsuki, H. Ichinose, S. Furuta, Growth of mullite whiskers on alumina particle by thermal decomposition of clay minerals, J. Ceram. Soc. Jpn. 104 (1996) 788-791.

DOI: 10.2109/jcersj.104.788

[9] J.R. Moyer, N.N. Hughes, A catalytic process for mullite whiskers, J. Am. Ceram. Soc. 77 (1994) 1083-1086.

[10] K. Okada, N. Ōtsuka, Synthesis of mullite whiskers by vapour-phase reaction, J. Mater. Sci. Soc. 8 (1989) 1052-1054.

DOI: 10.1007/bf01730484

[11] W.H. Jiang, Y.F. Peng, J.M. Liu, Preparation of mullite whisker via non-hydrolytic sol-gel route, J. Inorg. Mater. 25 (2010) 532-536.

DOI: 10.3724/sp.j.1077.2010.00532

[12] B.Q. Zhu, X.D. Li, R. Hao, Synthesis of mullite whisker in molten sodium sulphate, Refractory (in Chinese), 40 (2006) 165-168.

[13] L.L. Hench, J.K. West, The sol-gel process, Chem. Rev. 90 (1990) 33-72.

[14] W.H. Jiang, H.Y. Wei, G. Feng, Effect of oxygen donor alcohols on low temperature nonhydrolytic sol-gel synthesis of aluminum titanate, J. Chin. Ceram. Soc. 36 (2008) 11-16.

[15] W.S. Brower, H.S. Park, R.S. Roth, Phase equilibrium and crystal growth in the system lithium oxide-molybdenum oxide, J. Cryst. Growth. 16 (1972) 15-20.

DOI: 10.1016/0022-0248(72)90101-7