<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>J. Castaing</dc:contributor>
  <dc:contributor>T. E. Mitchell</dc:contributor>
  <dc:contributor>S. H. Kirby</dc:contributor>
  <dc:creator>A. K. Kronenberg</dc:creator>
  <dc:date>2000</dc:date>
  <dc:description>&lt;p&gt;Hydrogen impurities in materials influence their properties, including flow strength. &lt;i&gt;&amp;alpha;&lt;/i&gt;-Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; single crystals and polycrystalline ceramics were annealed in supercritical water between 850 and 1025&amp;deg;C, under pressures in the range 1500&amp;ndash;2000&amp;nbsp;MPa. A few specimens were further subjected to plastic deformation. Hydrogen penetration was examined using infrared absorption measurements of O&amp;ndash;H bond vibrations, which revealed two kinds of hydrogen defects. In single crystals, defects are characterized by sharp O&amp;ndash;H absorption bands assigned to interstitial protons. Hydrogen impurities of hydrothermally annealed ceramics and of all hydrothermally deformed specimens are characterized by broad O&amp;ndash;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.&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1016/S1359-6454(99)00448-6</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Elsevier</dc:publisher>
  <dc:title>Hydrogen defects in α-Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; and water weakening of sapphire and alumina ceramics between 600 and 1000°C: I. Infrared characterization of defects</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>