Mechanisms for silanol formation on amorphous silica fracture surfaces

Andrew S. D'Souza, Carlo G. Pantano

Research output: Contribution to journalArticle

63 Scopus citations

Abstract

Amorphous SiO 2 fracture surfaces created under different partial pressures of water vapor (P H2O) 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 SiO 2 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 H 2O 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 p H2O in the ambient atmosphere during the fracture process. It was also found that the number of strained siloxane bonds on the SiO 2 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
StatePublished - Dec 1 1999

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

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