Crystallization behavior of alkoxy-derived cordierite gels
Апстракт
Alkoxy-derived cordierite gels were synthesized from tetraethylorthosilicate (TEOS), aluminum isopropoxide (Al(OPri)(3)), and magnesium ethoxide (Mg(OEt)(2)). TEOS was partially hydrolyzed at molar ratios H2O/TEOS=1.2, in the presence of hydrochloric acid as a catalyst, HCl/TEOS=0.1. Aluminum and magnesium alkoxides were added successively or as a double alkoxide. Phase transformations occurring in the gel were studied by differential thermal analysis, x-ray diffractometry, and Fourier-transform infrared spectroscopy. In all cases, mu-cordierite crystallized at similar temperatures (950-1000degreesC) with small amounts of spinel, which confirms dominant influence of the optimal conditions for partial hydrolysis of TEOS on the gels homogeneity. The transformation of mu- into alpha-cordierite began at about 1100degreesC. Broadening of diffraction peaks and appearance of new bands in the FT IR spectra confirmed the transformation of alpha- into modulated beta-cordierite at temperatures ab...ove 1300degreesC. Differential thermal analysis under nonisothermal conditions also proved homogeneous nucleation with constant rate and three-dimensional crystallite growth during mu-cordierite crystallization. The overall activation energy of the crystallization of mu-cordierite is 580+/-81 kJ/mol.
Кључне речи:
cordierite / sol-gel process / phase transformations / kinetics of crystallizationИзвор:
Journal of Sol-gel Science and Technology, 2003, 28, 1, 111-118
DOI: 10.1023/A:1025649406466
ISSN: 0928-0707
WoS: 000185229200015
Scopus: 2-s2.0-0141990994
Колекције
Институција/група
VinčaTY - JOUR AU - Petrović, R AU - Janaćković, Đorđe T. AU - Zec, Slavica AU - Drmanic, S AU - Kostic-Gvozdenovic, LJ PY - 2003 UR - https://vinar.vin.bg.ac.rs/handle/123456789/2664 AB - Alkoxy-derived cordierite gels were synthesized from tetraethylorthosilicate (TEOS), aluminum isopropoxide (Al(OPri)(3)), and magnesium ethoxide (Mg(OEt)(2)). TEOS was partially hydrolyzed at molar ratios H2O/TEOS=1.2, in the presence of hydrochloric acid as a catalyst, HCl/TEOS=0.1. Aluminum and magnesium alkoxides were added successively or as a double alkoxide. Phase transformations occurring in the gel were studied by differential thermal analysis, x-ray diffractometry, and Fourier-transform infrared spectroscopy. In all cases, mu-cordierite crystallized at similar temperatures (950-1000degreesC) with small amounts of spinel, which confirms dominant influence of the optimal conditions for partial hydrolysis of TEOS on the gels homogeneity. The transformation of mu- into alpha-cordierite began at about 1100degreesC. Broadening of diffraction peaks and appearance of new bands in the FT IR spectra confirmed the transformation of alpha- into modulated beta-cordierite at temperatures above 1300degreesC. Differential thermal analysis under nonisothermal conditions also proved homogeneous nucleation with constant rate and three-dimensional crystallite growth during mu-cordierite crystallization. The overall activation energy of the crystallization of mu-cordierite is 580+/-81 kJ/mol. T2 - Journal of Sol-gel Science and Technology T1 - Crystallization behavior of alkoxy-derived cordierite gels VL - 28 IS - 1 SP - 111 EP - 118 DO - 10.1023/A:1025649406466 ER -
@article{ author = "Petrović, R and Janaćković, Đorđe T. and Zec, Slavica and Drmanic, S and Kostic-Gvozdenovic, LJ", year = "2003", abstract = "Alkoxy-derived cordierite gels were synthesized from tetraethylorthosilicate (TEOS), aluminum isopropoxide (Al(OPri)(3)), and magnesium ethoxide (Mg(OEt)(2)). TEOS was partially hydrolyzed at molar ratios H2O/TEOS=1.2, in the presence of hydrochloric acid as a catalyst, HCl/TEOS=0.1. Aluminum and magnesium alkoxides were added successively or as a double alkoxide. Phase transformations occurring in the gel were studied by differential thermal analysis, x-ray diffractometry, and Fourier-transform infrared spectroscopy. In all cases, mu-cordierite crystallized at similar temperatures (950-1000degreesC) with small amounts of spinel, which confirms dominant influence of the optimal conditions for partial hydrolysis of TEOS on the gels homogeneity. The transformation of mu- into alpha-cordierite began at about 1100degreesC. Broadening of diffraction peaks and appearance of new bands in the FT IR spectra confirmed the transformation of alpha- into modulated beta-cordierite at temperatures above 1300degreesC. Differential thermal analysis under nonisothermal conditions also proved homogeneous nucleation with constant rate and three-dimensional crystallite growth during mu-cordierite crystallization. The overall activation energy of the crystallization of mu-cordierite is 580+/-81 kJ/mol.", journal = "Journal of Sol-gel Science and Technology", title = "Crystallization behavior of alkoxy-derived cordierite gels", volume = "28", number = "1", pages = "111-118", doi = "10.1023/A:1025649406466" }
Petrović, R., Janaćković, Đ. T., Zec, S., Drmanic, S.,& Kostic-Gvozdenovic, L.. (2003). Crystallization behavior of alkoxy-derived cordierite gels. in Journal of Sol-gel Science and Technology, 28(1), 111-118. https://doi.org/10.1023/A:1025649406466
Petrović R, Janaćković ĐT, Zec S, Drmanic S, Kostic-Gvozdenovic L. Crystallization behavior of alkoxy-derived cordierite gels. in Journal of Sol-gel Science and Technology. 2003;28(1):111-118. doi:10.1023/A:1025649406466 .
Petrović, R, Janaćković, Đorđe T., Zec, Slavica, Drmanic, S, Kostic-Gvozdenovic, LJ, "Crystallization behavior of alkoxy-derived cordierite gels" in Journal of Sol-gel Science and Technology, 28, no. 1 (2003):111-118, https://doi.org/10.1023/A:1025649406466 . .