Hydrous lithium aluminosilicate (L–A–S–H) and lithium aluminate (L–A–H)
gels are candidate precursors for glass-ceramics and ceramics with potential
advantages over conventional processing routes. However, their structure before
calcination remained largely unknown, despite the importance of precursor
structure on the properties of the resulting materials. In the present study, it is
demonstrated that L–A–S–H and L–A–H gels with Li/Al ≤ 1 can be produced
via an organic steric entrapment route, while higher Li/Al ratios lead to crystallization
of gibbsite or nordstrandite. The composition and the structure of the
gels was studied by thermogravimetric analysis, X-ray diffraction, 27Al and 29Si
magic-angle spinning nuclear magnetic resonance, and Raman spectroscopy.
Aluminium was found to be almost exclusively in six-fold coordination in both
the L–A–H and the L–A–S–H gels. Silicon in the L–A–S–H gels was mainly in Q4
sites and to a lesser extent in Q3 sites (four-fold coordination with no Si–O–Al
bonds). The results thus indicate that silica-rich and aluminium-rich domains
formed in these gels.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:92261 |
| Date | 25 June 2024 |
| Creators | Simon, Sebastian, Bertmer, Marko, Gluth, Gregor J. G. |
| Publisher | John Wiley & Sons |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:article, info:eu-repo/semantics/article, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 1546-542X, 10.1111/ijac.14187 |
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