Mechanisms for silanol formation on amorphous silica fracture surfaces

Andrew S. D'Souza, Carlo G. Pantano

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65 Scopus citations

Abstract

Amorphous SiO2 fracture surfaces created under different partial pressures of water vapor (PH2O) were analyzed using temperature-programmed static secondary ion mass spectroscopy. The results were used to develop an atomistic model for the formation of a fracture surface. It was found that substantial reconstruction of the SiO2 fracture surface took place immediately after the fracture event. Formation of the fracture surface was modeled as three individual steps - rupture of Si-O-Si bonds to form dangling Si*and Si-O*bonds, reconstruction and relaxation of the surface to form both strained and unstrained siloxane bonds, and, lastly, reaction of H2O molecules with strained siloxane bonds to form surface silanol groups. The final concentration of surface silanol groups was found to have only a weak dependence on the pH2O in the ambient atmosphere during the fracture process. It was also found that the number of strained siloxane bonds on the SiO2 fracture surface could be substantially reduced by heat treatment of the glass under vacuum.

Original languageEnglish (US)
Pages (from-to)1289-1293
Number of pages5
JournalJournal of the American Ceramic Society
Volume82
Issue number5
DOIs
StatePublished - 1999

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

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