The Library
Evolution of crystalline aluminates from hybrid gel-derived precursors studied by XRD and multinuclear solid state MAS NMR IV: Calcium dialuminate, CaAl4O7 and calcium hexaluminate, CaAl12O19
Tools
UNSPECIFIED (2000) Evolution of crystalline aluminates from hybrid gel-derived precursors studied by XRD and multinuclear solid state MAS NMR IV: Calcium dialuminate, CaAl4O7 and calcium hexaluminate, CaAl12O19. THERMOCHIMICA ACTA, 363 (1-2). pp. 181-188. ISSN 0040-6031.
Research output not available from this repository.
Request-a-Copy directly from author or use local Library Get it For Me service.
Abstract
X-ray amorphous calcium aluminate gels of dialuminate and hexaluminate composition were prepared, the former by two methods, and their thermal crystallisation was monitored by thermal analysis, X-ray powder diffraction and Al-27 MAS NMR. Both gel compositions lose a large amount of solvent and organic by-products below 600 degreesC, forming amorphous precursors with Al-27 NMR spectra containing resonances corresponding to tetrahedral and octahedral sites, and another site with a peak at 36-39 ppm. The dialuminate gel crystallises abruptly at 900 degreesC to the essentially phase-purr compound containing Al predominantly in two distorted tetrahedral environments. The hexaluminate gel crystallises exothermically at 900 degreesC to gamma -alumina spinel, containing only tetrahedral and octahedral Al. The magnetoplumbite structure of the hexaluminate phase appears in an exothermic reaction at 1160 degreesC, this phase-pure reaction product containing Al atoms in one tetrahedral and two distinguishable octahedral sites. The first Ca-43 MAS NMR spectra of the crystalline dialuminate and hexaluminate are also reported. (C) 2000 Elsevier Science B,V. All rights reserved.
Item Type: | Journal Article | ||||
---|---|---|---|---|---|
Subjects: | Q Science > QD Chemistry | ||||
Journal or Publication Title: | THERMOCHIMICA ACTA | ||||
Publisher: | ELSEVIER SCIENCE BV | ||||
ISSN: | 0040-6031 | ||||
Official Date: | 27 November 2000 | ||||
Dates: |
|
||||
Volume: | 363 | ||||
Number: | 1-2 | ||||
Number of Pages: | 8 | ||||
Page Range: | pp. 181-188 | ||||
Publication Status: | Published |
Data sourced from Thomson Reuters' Web of Knowledge
Request changes or add full text files to a record
Repository staff actions (login required)
View Item |