beta-Al2TiO5 thin films were obtained by dip-coating silicon substrates in acid-catalyzed precursor sols of aluminum and titanium alkoxides with and without acetyl acetone as a chelating agent and subsequent firing at 700 degrees C. Nuclear magnetic resonance and mass spectra of the precursor sols demonstrated that synthesis without a chelating agent leads to the most extensive polymerization. X-ray photoelectron spectroscopy depth profiles showed that the composition of the films was homogeneous throughout their thicknesses. The crystallization of the films was studied as a function of the firing time and temperature. The films were amorphous up to 600 degrees C and, crystalline beta-Al2TiO5 was formed at 700 degrees C. From 800 up to 1200 degrees C, titania (anatase and rutile) :phases were also detected, without decomposition of the metastable beta-Al2TiO5, phase. The films fabricated from the sols without chelating agents showed a lower tendency to decompose into the thermodynamically stable phases rutile titania and alpha-Al2O3. The formation of beta-Al2TiO5 at low temperatures is attributed to a diffusion-limited crystallization process, which takes place in the conditions of high homogeneity at the molecular level reached in the sol-gel synthesis as shown by spectroscopic analysis.

Innocenzi, P., Martucci, A., Armelao, L., Licoccia, S., DI VONA, M.l., Traversa, E. (2000). Sol-gel synthesis of beta-Al2TiO5 thin films at low temperature. CHEMISTRY OF MATERIALS, 12(2), 517-524 [10.1021/cm991134i].

Sol-gel synthesis of beta-Al2TiO5 thin films at low temperature

LICOCCIA, SILVIA;DI VONA, MARIA LUISA;TRAVERSA, ENRICO
2000-01-01

Abstract

beta-Al2TiO5 thin films were obtained by dip-coating silicon substrates in acid-catalyzed precursor sols of aluminum and titanium alkoxides with and without acetyl acetone as a chelating agent and subsequent firing at 700 degrees C. Nuclear magnetic resonance and mass spectra of the precursor sols demonstrated that synthesis without a chelating agent leads to the most extensive polymerization. X-ray photoelectron spectroscopy depth profiles showed that the composition of the films was homogeneous throughout their thicknesses. The crystallization of the films was studied as a function of the firing time and temperature. The films were amorphous up to 600 degrees C and, crystalline beta-Al2TiO5 was formed at 700 degrees C. From 800 up to 1200 degrees C, titania (anatase and rutile) :phases were also detected, without decomposition of the metastable beta-Al2TiO5, phase. The films fabricated from the sols without chelating agents showed a lower tendency to decompose into the thermodynamically stable phases rutile titania and alpha-Al2O3. The formation of beta-Al2TiO5 at low temperatures is attributed to a diffusion-limited crystallization process, which takes place in the conditions of high homogeneity at the molecular level reached in the sol-gel synthesis as shown by spectroscopic analysis.
2000
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore CHIM/07 - FONDAMENTI CHIMICI DELLE TECNOLOGIE
Settore ING-IND/22 - SCIENZA E TECNOLOGIA DEI MATERIALI
English
Con Impact Factor ISI
aluminum derivative; aluminum oxide; beta aluminum titanate; chelating agent; titanium derivative; titanium dioxide; unclassified drug; article; carbon nuclear magnetic resonance; catalysis; chelation; chemical analysis; decomposition; diffusion; film; hydrolysis; low temperature; mass spectrometry; nuclear magnetic resonance spectroscopy; polymerization; reaction analysis; roentgen spectroscopy; structure analysis; temperature sensitivity; thermodynamics; thermostability; thickness
Innocenzi, P., Martucci, A., Armelao, L., Licoccia, S., DI VONA, M.l., Traversa, E. (2000). Sol-gel synthesis of beta-Al2TiO5 thin films at low temperature. CHEMISTRY OF MATERIALS, 12(2), 517-524 [10.1021/cm991134i].
Innocenzi, P; Martucci, A; Armelao, L; Licoccia, S; DI VONA, Ml; Traversa, E
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/44044
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