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

Plinio Innocenzi*, Alessandro Martucci, Lidia Armelao, Silvia Licoccia, Maria Luisa Di Vona, Enrico Traversa

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

β-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 °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 °C and crystalline β-Al2TiO5 was formed at 700 °C. From 800 up to 1200 °C, titania (anatase and rutile) phases were also detected, without decomposition of the metastable β-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 α-Al2O3. The formation of β-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.

Original languageEnglish (US)
Pages (from-to)517-524
Number of pages8
JournalChemistry of Materials
Volume12
Issue number2
DOIs
StatePublished - Feb 1 2000

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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