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27 Al Nuclear Magnetic Resonance of Glassy and Crystalline Zr (1−x) Al x O (2−x/2) Materials Prepared from Solution Precursors
Author(s) -
Balmer Mari Lou,
Eckert Hellmut,
Das Nandini,
Lange Fred F.
Publication year - 1996
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1996.tb08123.x
Subject(s) - amorphous solid , magic angle spinning , coordination number , materials science , crystallization , aluminium , metastability , crystallography , melt spinning , valence (chemistry) , solid state nuclear magnetic resonance , ion , analytical chemistry (journal) , nuclear magnetic resonance , chemistry , nuclear magnetic resonance spectroscopy , spinning , metallurgy , physics , organic chemistry , composite material , chromatography
The local environment of the aluminum atoms in a series of metastable Zr (1− x ) Al x O (2− x/ 2) crystalline materials (0.08 ≤ x ≤ 0.57), prepared by diffusion‐limited crystallization of amorphous precursors, has been determined by 27 Al magic angle spinning nuclear magnetic resonance (MAS NMR). Results show the existence of aluminum in 4‐, 5‐, and 6‐fold coordination in both the amorphous and crystalline states. Although the relative amounts of each type of coordination show no compositional dependence in the amorphous state, the results for the crystalline materials show a systematic decrease in the average aluminum coordination number with increasing aluminum content. Comparisons of MAS NMR results between pure Al 2 O 3 precursors and Zr (1‐ x ) Al x O (2‐ x /2) crystalline materials processed under similar conditions show a profound effect of ZrO 2 on the coordination environment of the aluminum atom. Both a random distribution model and a model that assumes small‐scale clustering of aluminum ions are considered to explain the trends in the type of aluminum coordination as a function of composition.