Evolution of aluminosilicate structure and mullite crystallization from homogeneous nanoparticulate sol–gel precursor with organic additives
✍ Scribed by Jarkko Leivo; Mika Lindén; Jessica M. Rosenholm; Merja Ritola; Cilâine V. Teixeira; Erkki Levänen; Tapio A. Mäntylä
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 884 KB
- Volume
- 28
- Category
- Article
- ISSN
- 0955-2219
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✦ Synopsis
The influence of non-ionic polyethylene glycol and poly(vinylpyrrolidone) on monophasic-like nanoparticulate aluminosilicate with mullite bulk composition was investigated. The chemical homogeneity in the sol-gel state, as well as the evolution of the calcined aluminosilicate/mullite structures thereof, was studied by dynamic laser scattering, small angle X-ray scattering, nuclear magnetic resonance spectroscopy, X-ray diffraction, differential thermal analysis, dilatometry, N 2 adsorption and Fourier transform infrared spectroscopy. The results show that the organic additives have virtually no influence on the chemical structure of the monophasic-like nanoparticles in the sol-gel state, and the overall homogeneity of monophasic gels in the fired ceramics was generally sustained, as judged by the Type I crystallization. The porosity was not due to the polymers directly acting as porogens, but due to voids formed during the restructuring of matter during heat treatment.