Hydrogen defects in alpha-Al2O3 and water weakening of sapphire and alumina ceramics between 600 and 1000 degrees C - I. - Infrared characterization of defects Academic Article uri icon


  • Hydrogen impurities in materials influence their properties, including flow strength. -Al2O3 single crystals and polycrystalline ceramics were annealed in supercritical water between 850 and 1025C, 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.

published proceedings


author list (cited authors)

  • Kronenberg, A. K., Castaing, J., Mitchell, T. E., & Kirby, S. H.

citation count

  • 39

complete list of authors

  • Kronenberg, AK||Castaing, J||Mitchell, TE||Kirby, SH

publication date

  • April 2000