Atomistic structure of calcium silicate intergranular films in alumina studied by molecular dynamics simulations

Slawomir Blonski, Stephen H. Garofalini

Research output: Contribution to journalArticlepeer-review

80 Citations (Scopus)

Abstract

Molecular dynamics simulations of calcium silicate (CaSiO3) intergranular films that were formed during the liquid-phase sintering of alumina (Al2O3) ceramics were conducted. A constant-pressure algorithm was used in the simulations to accommodate changes in the sample size during heat treatment and tensile tests. A model of the grain boundary that was wetted by glass was created by melting the silicate film between two Al2O3 surfaces with the basal orientation. Samples with different film thicknesses and CaO contents were studied. The presence of an ordered interface in the atomistic structure of the mostly amorphous films was revealed. Calcium additives segregated preferentially into the ordered SiO2/Al2O3 interface regions. Increased addition of calcium further promoted the ordering and increased stability of the films. Tensile strength was evaluated and showed an increase with low calcium additions, followed by strength reduction at higher CaO additions. Two modes of fracture were observed in the simulations.

Original languageEnglish
Pages (from-to)1997-2004
Number of pages8
JournalJournal of the American Ceramic Society
Volume80
Issue number8
DOIs
Publication statusPublished - Aug 1997

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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