Research output: Contribution in Book/Report/Proceedings - With ISBN/ISSN › Conference contribution/Paper › peer-review
Research output: Contribution in Book/Report/Proceedings - With ISBN/ISSN › Conference contribution/Paper › peer-review
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TY - GEN
T1 - Characterization of near surface mechanical properties of ion-exchanged glasses using Surface Brillouin Spectroscopy.
AU - Puentes, S. M.
AU - Bradshaw, J.
AU - Briggs, G. Andrew D.
AU - Kolosov, Oleg
AU - Bowen, K.
AU - Loxley, N.
PY - 1998
Y1 - 1998
N2 - The technique of Surface Brillouin Spectroscopy is attracting considerable attention for the non-destructive characterization of near-surface properties that depend upon the elastic behaviour. These include surface strengthening, delamination in metallised layers and structural changes near surfaces. We here present a study of the chemical strengthening of glass. SBS measurements of surface acoustic wave (SAW) velocity in glasses strengthened by the exchange of K+ for Na+ ions were carried out using the Bede BriSc instrument.The study of surface acoustic waves on a transparent material such as glass was made possible by depositing a thin layer of aluminium on the glass surface. At a working frequency of 20 GHz, the optimum thickness of the layer was found to be 30 nm. The replacement of Na+ by K+ ions that takes place during the treatment of the glass causes near-surface modifications of both density and elastic constants. An increase of 3.8% in density due to the replacement of light Na+ ions by heavier K+ ions at the surface could account only for a 1.9% decrease in the surface acoustic wave velocity. Residual stresses were estimated to have a negligible effect on surface acoustic wave velocity. At the same time a 2.8+/-0.4% decrease in the surface acoustic wave velocity due to the ion-exchange process was observed by SBS. This result suggests that a significant part of the surface acoustic wave (SAW) velocity change should be attributed to variations in the elastic constants (approximately 1.8%) and agrees well with independent estimates of the Young's modulus (E) and shear modulus (C-44) changes caused by replacing the Na+ ions by K+ ions during the process.
AB - The technique of Surface Brillouin Spectroscopy is attracting considerable attention for the non-destructive characterization of near-surface properties that depend upon the elastic behaviour. These include surface strengthening, delamination in metallised layers and structural changes near surfaces. We here present a study of the chemical strengthening of glass. SBS measurements of surface acoustic wave (SAW) velocity in glasses strengthened by the exchange of K+ for Na+ ions were carried out using the Bede BriSc instrument.The study of surface acoustic waves on a transparent material such as glass was made possible by depositing a thin layer of aluminium on the glass surface. At a working frequency of 20 GHz, the optimum thickness of the layer was found to be 30 nm. The replacement of Na+ by K+ ions that takes place during the treatment of the glass causes near-surface modifications of both density and elastic constants. An increase of 3.8% in density due to the replacement of light Na+ ions by heavier K+ ions at the surface could account only for a 1.9% decrease in the surface acoustic wave velocity. Residual stresses were estimated to have a negligible effect on surface acoustic wave velocity. At the same time a 2.8+/-0.4% decrease in the surface acoustic wave velocity due to the ion-exchange process was observed by SBS. This result suggests that a significant part of the surface acoustic wave (SAW) velocity change should be attributed to variations in the elastic constants (approximately 1.8%) and agrees well with independent estimates of the Young's modulus (E) and shear modulus (C-44) changes caused by replacing the Na+ ions by K+ ions during the process.
M3 - Conference contribution/Paper
SN - 0-306-45900-0
SP - 817
EP - 823
BT - Nondestructive Characterization of Materials VIII
A2 - Green, R. E.
PB - Plenum Press
CY - New York
T2 - 8th International Symposium on Nondestructive Characterization of Materials
Y2 - 15 June 1997 through 20 June 1997
ER -