Boehmite coating on θ-Al2O3 particles via a sol-gel route

Lung Teng Cheng, Mong Yen Tsai, Wenjea J. Tseng, Hsing-I Hsiang, Fu Su Yen

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

θ-Al2O3 powders in slurry form were coated by boehmite nanoparticles prepared from alumina sol that consists of aluminum tri-sec-butoxide (Al(OC4H9)3) as a precursor. The θ-Al2O3 powders presented an iso-electrical point (IEP) at pH ∼ 9.2, and formed stable suspensions without notable gravity settling at acidic conditions (pH 3-4). Boehmite nanoparticles with a mean particle size ca. 68 nm were derived from the hydrolysis of Al(OC4H9)3 sol. Well-dispersed boehmite/θ-Al2O3 aqueous mixtures consisting of 3 and 9 wt.% of boehmite were then prepared by addition of θ-Al2O3 powder into the Al(OC4H9)3 sol followed then by vigorous agitation at 90 °C and in a pH range 3-4. IR and particle-size measurement both revealed possible coating of boehmite on the θ-Al2O3 particles. From TEM observation, "thickness" of the boehmite layer did not vary much with the boehmite concentration. Agglomeration of the particles became nonetheless apparent as the boehmite concentration was increased. The boehmite coating on θ-Al2O3 surface inhibited grain growth during the θ- to α-phase transformation upon heating. Mean grain size of the boehmite-coated alumina was substantially smaller than that of the un-coated one.

Original languageEnglish
Pages (from-to)337-343
Number of pages7
JournalCeramics International
Volume34
Issue number2
DOIs
Publication statusPublished - 2008 Mar 1

Fingerprint

Sols
Particles (particulate matter)
Sol-gels
Powders
Coatings
Alumina
Particle size
Nanoparticles
Grain growth
Polymethyl Methacrylate
Hydrolysis
Gravitation
Agglomeration
Phase transitions
Aluminum Oxide
Transmission electron microscopy
Aluminum
Heating
aluminum oxide hydroxide
Suspensions

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Cheng, Lung Teng ; Tsai, Mong Yen ; Tseng, Wenjea J. ; Hsiang, Hsing-I ; Yen, Fu Su. / Boehmite coating on θ-Al2O3 particles via a sol-gel route. In: Ceramics International. 2008 ; Vol. 34, No. 2. pp. 337-343.
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Boehmite coating on θ-Al2O3 particles via a sol-gel route. / Cheng, Lung Teng; Tsai, Mong Yen; Tseng, Wenjea J.; Hsiang, Hsing-I; Yen, Fu Su.

In: Ceramics International, Vol. 34, No. 2, 01.03.2008, p. 337-343.

Research output: Contribution to journalArticle

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