Studies on the Formation of Mullite from Diphasic Al2O3-SiO2 Gel by Fourier Transform Infrared Spectroscopy

Document Type : Research Article


1 Camellia Institute of Technology, Badu, Madhyagram, Kokata-700127, INDIA

2 Govt. College of Engineering and Ceramic Technology, 73, A.C. Banerjee Lane, Kolkata-700010, INDIA

3 Mechanical and Metallurgical Engineering Department, Florida International Univeristy, USA


Al2O3-SiO2 diphasic gel was synthesized by sol gel route from aluminium nitrate and silicic acid following aqueous phase colloidal interaction. The precursor gel powder was thoroughly characterized by chemical analysis, measurement of surface area and bulk density measurement. The gel powder was further characterized by thermogravimetry, XRD diffraction study of the heat treated samples and Scanning Electron Microscopic (SEM) study of the fractured surfaces of the heat treated compacts. The gel was observed to be a truly di-phasic in nature and was capable of forming nano-structured well distributed mullite phase in the microstructure of the heat treated sample. The gel powder was heated at different temperatures and the formation of Al-O-Si linkage towards the formation of mullite phase (3Al2O3 , 2SiO2) was studied by Fourier Transform Infra Red (FT-IR) spectroscopy. The characteristic Al-O-Si linkage was found to develop after 600oC indicating the formation of mullite gel  and at 16000oC the linkage became very strong indicating complete crystallization of mullite.


Main Subjects

[1] Kollenberg,W., Schneider H., Microhardness of Mullite at Temperatures to 1000, J. Am. Ceram. Soc., 72, p. 1739 (1989).
[2] Hynes A.P., Doremus R.H., High-Temperature Compressive Creep of Polycrystalline Mullite, J. Am. Ceram Soc., 74, p. 2469 (1991).
[3] Aksay A., Dabbs D.M., Sarikaya M., Mullite for Structural, Electronic, and Optical Applications, J. Am. Ceram. Soc., 74, p. 2343 (1991).
[4] Schneider H., Eberhard E.,Thermal Expansion of Mullite, J Am. Ceram. Soc., 73, p. 2073 (1990).
[5] Kanka B., Schneider H., Sintering Mechanisms and Micro-Structural Development of Co-Precipitated Mullite, J. Mater. Sci., 29, p. 1239 (1994).
[6] Sarikaya M., Aksay, I.A., Spinel Phase Formation During the 980 °C Exothermic Reaction in the Kaolinite-to-Mullite Reaction Series, J. Am. Ceram. Soc., 70, p. 837 (1987).
[7] Cameron W.E., Mullite: a substituted Alumina, Am. Miner., 62, p. 747 (1977).
[8] Somiya S., Hirata Y., Mullite Powder Technology and Applications in Japan, Ceram. Bull, 70, p. 1624 (1991).
[9] DavisR.F., Pask J.A., in : Alper A.M., ed., "High Temperature Oxides", Academic Press,New York, p. 37 (1971).
[10] Hench L.L., Vasconcelos W.L., Sol-Gel Process Using Aluminum Oxychloride, Aluminosilicate and Aluminum Borosilicate, Annu. Rev. Mater. Sci., 20, p. 269 (1990).
[11] Hench L.L., West J.K., The Sol-Gel Process, Chem. Rev., 90, p. 33 (1990).
[12] Komarneni S.,  Some  Significant  Advances  in Sol-Gel Processing of Dense Structural Ceramics,
J. Sol-Gel Sci. Tech. 6, p. 127 (1996).
[13] Schneider H., Saruhan B., Voll D., Merwin L., Mullite Precursor Phases, J. Eur. Ceram. Soc., 11, p. 87 (1993).
[14] Hoffman D.W., Roy R., Komareni S., Diphasic Xerogels, A New Class of Materials: Phases in the System Al2O3-SiO2, J. Am. Ceram. Soc., 67, p. 468 (1984).
[15] Chakravorthy A.K., Ghosh D.K.,Kaolinite-Mullite Reaction Series: The Development and Significance of a Binary Aluminosilicate Phase, J. Am. Ceram. Soc., 74, p. 2359 (1991).
[16] Schneider H., Voll D., Sahuran B., Sanz J., Schrader G., Ruscher C., Mosset A., Synthesis and Structural Characterization of Non-Crystalline Mullite Precursors, J. Non-Cryst. Soid, 178, p. 262 (1994)
[17] JaymersI., Douy A., Homogeneous Precipitation of Mullite Precursors, J. Sol-Gel Sci. Tech, 4, p.7 (1995).
[18] Pach L., Iratni A., Hrabe Z., Svetik S., Komarneni S.S., Sintering and Crystallization of Mullite in Diphasic Gels, J. Mater. Sci., 30, p. 5490 (1995).
[19] Heinrich T., Raether E., Marsmann H., Growth and Structure of Single Phase Mullite Gles from Chelated Aluminum Alkoxides and Alkoxysilanes, J. Non-Cryst. Solid, 168, p.14 (1994).
[20] Epicier T., Benefits of High-Resolution Electron Microscopy for Structural Characterization of Mullites, J. Am Ceram. Soc., 74, p. 2359 (1991).
[21] Kuper G., Peitz B., WinterI., Hormes J., Schneider H., Schumeker M., Voll D., Aluminum K-Edge Absorption (XANES) Studies of Noncrystalline Mullite Precursors, J. Am. Ceram. Soc., 81, p. 813 (1996).
[22] Jaymes I., Douy A., Massiot D., Counters J.P., Characterization of Mono- and Diphasic Mullite Precursor Powders Prepared by Aqueous Routes. 27Al and 29Si MAS-NMR Spectroscopy Investigations, J. Mater Sci., 31, p. 4581 (1996).
[23] Schneider H.,  Merwin L.,  Sebald A.,  Mullite Formation from Non-Crystalline Precursors, J. Mater. Sci., 27, p. 805 (1992).
[24] Kansal P., Laine R.M., Babonnean F., A Processable Mullite Precursor Prepared by Reacting Silica and Aluminum Hydroxide with Triethanolamine in Ethylene Glycol: Structural Evolution on Pyrolysis, J. Am. Ceram. Soc., 80, p. 2597 (1997).
[25] Li D.X., Thomson W.J., Mullite Formation from Nonstoichiometric Diphasic Precursors, J. Am. Ceram. Soc., 73, p. 9641 (1990).
[26] Ruscher C.H.,  Schrader G.,  Gotte M.,  Infra-red Spectroscopic Investigation in the Mullite Field of Composition: Al2(Al2+2xSi2-2x)O10-x with 0.55>x>0.25, J. Eur. Ceram. Soc., 161, p. 69 (1996).
[27] Janackovic D.J., Jakanovic V., Kostic-Gvozdenovic L.J., Uskokovic D., Modeling of Nanostructural Design Using Ultrasonic Spray Pyrolysis, Nanostruc. Mater., 10, p. 341, (1998).
[28] Okada K., Otsuka N., Characterization of the Spinel Phase from SiO2-Al2O3 Xerogels and the Formation Process of Mullite, J. Am. Ceram. Soc., 69, p. 652 (1986).
[29] Orefice B.L., Vasconcelos W.L., Sol-Gel Transition and Structural Evolution on Multicomponent Gels Derived from the Alumina-Silica System, J. Sol-Gel Sci Tech., 9, p. 239 (1977).
[30] Bertoluzaa A., Fagnano C., Moreli M.A., Gottardi V., Raman and Infraded Spectra on Silica Gel Evolving Toward Glass, Guglielni M.J., J. Non-Cryst, Solids, 53, p. 279 (1982).