Article

Review of Mullite Synthesis Routes by Sol–Gel Method

Journal of Sol-Gel Science and Technology (Impact Factor: 1.53). 07/2010; 55(1):111-125. DOI: 10.1007/s10971-010-2222-9

ABSTRACT

The sol–gel method for the mullite synthesis is reviewed, with particular emphasis on the characterization of monophasic and
diphasic gels at low, intermediate and high temperatures and the factors that influence the hydrolysis and condensation rate
of the sol–gel process, which in turn determine the properties of the final material. A wide range of studies about mullite
precursors synthesized via sol–gel is discussed here.

KeywordsSol–gel-Mullite-Monophasic-Diphasic-Additives

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    • "Production of mullite from alumina and silica sols indicated that amorphous mullite forms at around 600 1C and can be sintered into dense mullite at 1600 1C [16]. Previous study by Cividanes et al. [17] revealed that mullitization lies at the "
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    ABSTRACT: The sol-gel synthesis and characterization of mullite precursor derived from rice husk silica and aluminum nitrate hydrate [(Al(NO3)(3)center dot 9H(2)O] has been investigated. The samples were characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) coupled with Rietveld analysis, and scanning electron microscopy (SEM). FTIR results showed the presence of Si-O-Si, Al-O-Al, and Si-O-Al functional groups, which were associated with mullite, corundum, quartz, and cristobalite, as verified by XRD analysis. It is concluded that mullite formation started at 1150 degrees C, and its abundance increased rapidly with an increase in temperature from 1150 to 1350 degrees C, resulting in increased phase content from 30.9 to 67.7 wt%. Although mullite was formed at a low temperature, the complete reaction between corundum and silica to form mullite was not achieved. This finding demonstrated that rice husk silica is a potential alternative raw material for the production of mullite ceramic. Crown Copyright
    Full-text · Article · Jun 2014 · Ceramics International
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    • "All the characteristic bands of mullite, 561 (AlO 6 ), 741(AlO 4 ), 837(AlO 4 ), 900(AlO 4 stretching mode) and 1 141 cm 1 (Si–O stretching mode) appear in all the doped samples of 1 000 ℃ sintered gels ,but 900(AlO 4 stretching mode) is not obtained, but rest of the bands are obtained in all doped samples of 1 300 ℃ sintered gels . Absence of band around 1 170 cm 1 indicates primarily a tetragonal geometry for mullite [25] [26] [27] . 3.4 Lattice parameters Mullite crystallizes in orthorhombic system and its unit cell is characterized with three lallice parameters. "

    Full-text · Dataset · Mar 2013
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    • "All the characteristic bands of mullite, 561 (AlO 6 ), 741(AlO 4 ), 837(AlO 4 ), 900(AlO 4 stretching mode) and 1 141 cm 1 (Si–O stretching mode) appear in all the doped samples of 1 000 ℃ sintered gels ,but 900(AlO 4 stretching mode) is not obtained, but rest of the bands are obtained in all doped samples of 1 300 ℃ sintered gels . Absence of band around 1 170 cm 1 indicates primarily a tetragonal geometry for mullite [25] [26] [27] . 3.4 Lattice parameters Mullite crystallizes in orthorhombic system and its unit cell is characterized with three lallice parameters. "
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    ABSTRACT: Monophasic mullite (3Al2O3•2SiO2) samples doped with 0.002 M, 0.02 M, 0.1 M, 0.15 M and 0.2 M of cobalt were prepared by a sol-gel process. Prepared gels were then dried, grinded, pressed into pellets and sintered at 1 000 °C and 1 300 °C for 4 h. Phase formation and densifi cation behavior has been investigated as a function of the cobalt content and sintering temperature. Mullite densifi cation behavior was analyzed .The density of the sintered ceramics was measured using Archimedes method. CoO and Co related compounds were detected by the analysis for G3, G4 and G5 doping levels. The mullite X-ray diffraction suggests predominant incorporation of Co in the glassy phase, whose quantity increased with the doping level.
    Full-text · Article · May 2012 · Journal of Wuhan University of Technology-Mater Sci Ed
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