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Abstract <p>The mullite precursor was synthesized by burning a xerogel obtained from a mixture of aluminum nitrate, highly dispersed silicon dioxide in the form of AEROSIL, urea as a fuel (reducing agent) and hydrogen peroxide as an auxiliary additive. Using thermal, X-ray, IR-spectral, NMR methods, the crystallization of the precursor, i.e., its transition to mullite 3Al<sub>2</sub>O<sub>3</sub>⋅2SiO<sub>2</sub>, was studied. The synthesized powder was an amorphous product that crystallized under heat treatment (1100°C). The burning at 1200°C made it possible to obtain a well-crystallized single-phase mullite. The presence of groups AlO<sub>4</sub>, AlO<sub>5</sub>, and AlO<sub>6</sub> was found in the combustion product. The precursor thermal analysis at different heating rates according to the position of exothermic peaks corresponding to the mullite crystallization allowed to estimate the effective activation energy.</p>

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Crystallization of a Mullite Precursor Obtained by Combustion

  • 期刊论文

  • 发表日期：

    2025年10月16日

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  • N. V. Filatova,
  • N. F. Kosenko,
  • M. A. Badanov

摘要

Abstract

The mullite precursor was synthesized by burning a xerogel obtained from a mixture of aluminum nitrate, highly dispersed silicon dioxide in the form of AEROSIL, urea as a fuel (reducing agent) and hydrogen peroxide as an auxiliary additive. Using thermal, X-ray, IR-spectral, NMR methods, the crystallization of the precursor, i.e., its transition to mullite 3Al2O3⋅2SiO2, was studied. The synthesized powder was an amorphous product that crystallized under heat treatment (1100°C). The burning at 1200°C made it possible to obtain a well-crystallized single-phase mullite. The presence of groups AlO4, AlO5, and AlO6 was found in the combustion product. The precursor thermal analysis at different heating rates according to the position of exothermic peaks corresponding to the mullite crystallization allowed to estimate the effective activation energy.