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Hydrogen defects in α-Al2O3 and water weakening of sapphire and alumina ceramics between 600 and 1000°C: I. Infrared characterization of defects

Acta Materialia

By:
, , , and
DOI: 10.1016/S1359-6454(99)00448-6

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Abstract

Hydrogen impurities in materials influence their properties, including flow strength. α-Al2O3 single crystals and polycrystalline ceramics were annealed in supercritical water between 850 and 1025°C, under pressures in the range 1500–2000 MPa. A few specimens were further subjected to plastic deformation. Hydrogen penetration was examined using infrared absorption measurements of O–H bond vibrations, which revealed two kinds of hydrogen defects. In single crystals, defects are characterized by sharp O–H absorption bands assigned to interstitial protons. Hydrogen impurities of hydrothermally annealed ceramics and of all hydrothermally deformed specimens are characterized by broad O–H bands assigned to molecular water. The grain boundaries of hydrothermally annealed ceramics are severely damaged. The kinetics of hydrogen penetration is consistent with diffusion data.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Hydrogen defects in α-Al2O3 and water weakening of sapphire and alumina ceramics between 600 and 1000°C: I. Infrared characterization of defects
Series title:
Acta Materialia
DOI:
10.1016/S1359-6454(99)00448-6
Volume
48
Issue:
7
Year Published:
2000
Language:
English
Publisher:
Elsevier
Description:
14 p.
First page:
1481
Last page:
1494
Online Only (Y/N):
N
Additional Online Files(Y/N):
N