Chadwick, A.V. and Strange, J.H. and Mountjoy, G. and Tucker, M.G. and Smith, M.E. and Nield, V.M. and Poplett, I.J.F, (2001) Solid state NMR and X-ray studies of the structural evolution of nanocrystalline zirconia. CHEMISTRY OF MATERIALS , 13 (4). pp. 1219-1229. ISSN 0897-4756 .
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| Official URL http://dx.doi.org/10.1021/cm001152w |
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Abstract
A combination of X-ray techniques [diffraction and Zr K-edge absorption (EXAFS and XANES)] and multinuclear (H-1, C-13, O-17) solid-state NMR spectroscopy is employed to follow in detail the structural development of nanocrystalline zirconia. O-17 magic-angle spinning NMR spectroscopy of sol-gel produced undoped ZrO2 shows unequivocally that oxygen sites in the initial gel are monoclinic-like. This result is consistent with X-ray absorption measurements, which also suggest that the structures of the initial amorphous phases of doped and undoped samples produced by the hydroxide-precipitation and sol-gel methods are very similar. On crystallization, the local structure of the crystalline component is tetragonal, but a significant fraction of the sample remains disordered. Heating to higher temperatures results in conversion to monoclinic zirconia in undoped samples at room temperature. For sol-gel-produced ZrO2, C-13 NMR shows that loss of all of the organic fragments occurs prior to crystallization. The H-1 NMR experiments determined that the proton content remains significant until well above the crystallization temperature, so that the composition is not accurately described as ZrO2 until > 500 degreesC.
| Item Type: | Article |
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| Subjects: | Q Science |
| Divisions: | Faculties > Science Technology and Medical Studies > School of Physical Sciences > Functional Materials Group Faculties > Science Technology and Medical Studies > School of Physical Sciences |
| Depositing User: | Alan Chadwick |
| Date Deposited: | 09 Oct 2008 14:33 |
| Last Modified: | 06 Sep 2011 00:22 |
| Resource URI: | http://kar.kent.ac.uk/id/eprint/9398 (The current URI for this page, for reference purposes) |
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