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Crystal Structure, Short-Range Oxygen Defects, and Water Adsorption in La- and Nd-Modified ZrO2

Published online by Cambridge University Press:  22 February 2011

C.-K. Loong
Affiliation:
ARGONNE National Lab., Argonne, IL 60439, U. S. A.
J. W. Richardson JR.
Affiliation:
ARGONNE National Lab., Argonne, IL 60439, U. S. A.
L. E. Iton
Affiliation:
ARGONNE National Lab., Argonne, IL 60439, U. S. A.
M. Ozawa
Affiliation:
Nagoya Institute of Technology, Tajimi, Gifu, 507, Japan.
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Abstract

Doping Rare-earth (RE) elements to ZrO2 helps stabilize the cubic and tetragonal phases and improves resistance to thermal shock and sintering at high temperatures. Since a RE ion has a lower valency (3+) than Zr ion (4+), oxygen vacancies are formed to preserve electroneutrality. We have studied the crystal structure of La0.1Zro.9O1.95 and Nd0.1Zr0.9O1.95 by neutron diffraction and examined the associated oxygen defects by a Fourier transform of the filtered residual diffuse scattering. The hydration process was investigated by inelastic neutron-scattering measurements of the hydrogen vibrational density of states of the surface hydroxyl groups and physisorbed water on these fine powders. We compare the O-H stretch vibrations from samples with only surface hydroxyl groups to multilayer coverage of water molecules. The decreasing energies and increasing widths of the O-H stretch bands with increasing H2O coverage indicate the influence of hydrogen bonding on the motion of water molecules. Similar elastic and inelastic experiments were also performed on a high surface-area pure ZrO2 powder.

Type
Research Article
Copyright
Copyright © Materials Research Society 1995

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References

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