Effect of mechanochemical activation on the thermal reactions of boehmite (γ-AlOOH) and γ-Al2O3

K. J D MacKenzie, J. Temuujin, M. E. Smith, P. Angerer, Yoshikazu Kameshima

Research output: Contribution to journalArticle

73 Citations (Scopus)

Abstract

Boehmite (γ-AlOOH) and γ-Al2O3 were ground for 60 min and the changes in their structure and thermal reactions were monitored by X-ray powder diffraction, thermal analysis and 27Al MAS NMR. Grinding does not cause the boehmite to dehydrate, but causes a decrease in the intensity of its X-ray reflections, and the formation of an amorphous phase containing tetrahedral Al and another Al site with a resonance at 36 ppm (sometimes attributed to pentacoordinated Al). The ground material thermally transforms to corundum at 940°C via γ-Al2O3, by contrast with the unground control, which forms corundum at 1195°C via γ and δ-Al2O3. Grinding γ-Al2O3 decreases the intensity of its X-ray reflections and induces the formation of some corundum without further heating. Complete transformation to corundum occurs at 927°C, compared with 1193°C in the unground material which transforms via δ-Al2O3. The relationship between the mechanochemical development of the 36 ppm 27Al NMR resonance in aluminas and their hydroxyl and adsorbed water content is discussed. (C) 2000 Elsevier Science B.V.

Original languageEnglish
Pages (from-to)87-94
Number of pages8
JournalThermochimica Acta
Volume359
Issue number1
DOIs
Publication statusPublished - Aug 21 2000
Externally publishedYes

Fingerprint

Corundum
Aluminum Oxide
aluminum oxides
Chemical activation
activation
grinding
Nuclear magnetic resonance
X rays
nuclear magnetic resonance
x rays
X ray powder diffraction
Thermoanalysis
Water content
causes
Alumina
Hydroxyl Radical
moisture content
thermal analysis
Heating
Hot Temperature

Keywords

  • Alumina
  • Mechanochemical activation
  • Thermal reactions

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Effect of mechanochemical activation on the thermal reactions of boehmite (γ-AlOOH) and γ-Al2O3 . / MacKenzie, K. J D; Temuujin, J.; Smith, M. E.; Angerer, P.; Kameshima, Yoshikazu.

In: Thermochimica Acta, Vol. 359, No. 1, 21.08.2000, p. 87-94.

Research output: Contribution to journalArticle

MacKenzie, K. J D ; Temuujin, J. ; Smith, M. E. ; Angerer, P. ; Kameshima, Yoshikazu. / Effect of mechanochemical activation on the thermal reactions of boehmite (γ-AlOOH) and γ-Al2O3 . In: Thermochimica Acta. 2000 ; Vol. 359, No. 1. pp. 87-94.
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