Grain-boundary sliding in fluorine-doped silicon nitride

Journal Article · Sat Mar 01 04:00:00 EST 1997 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1997.tb02873.x· OSTI ID:474139

Pezzotti, G ^[1]; Ota, Kenichi ^[2]

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1. Kyoto Inst. of Tech., Matsugasaki, Kyoto (Japan). Dept. of Materials
2. Osaka Univ., Ibaraki, Osaka (Japan). Inst. of Scientific and Industrial Research

A systematic study of the effect of small additions of fluorine impurity on the relaxation and creep behavior of Si{sub 3}N{sub 4} ceramics was conducted. A model polycrystal, consisting of equiaxed grains and containing only pure (glassy) SiO{sub 2} at the grain boundary, was selected for this investigation. The boundary SiO{sub 2}-glass film, completely surrounding the grains, was doped with increased amounts of the glass-network modifier fluorine to systematically lower its bulk viscosity. The addition of the fluorine made both the grain-boundary relaxation peak and the background of internal friction notably shift toward lower temperatures; the scaling was in accordance with the lowered viscosity of the bulk fluorine-doped SiO{sub 2} glass. Invoking basic viscoelasticity principles, the grain-boundary relaxation phenomenon could be rationalized and the internal friction data consistently related to the macroscopic (torsional) creep behavior of the polycrystal.

• Sponsoring Organization: USDOE
• OSTI ID: 474139
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 3 Vol. 80; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CREEP
FLUORINE ADDITIONS
GRAIN BOUNDARIES
INTERFACES
INTERNAL FRICTION
SILICON NITRIDES
SILICON OXIDES
STRESS RELAXATION
VISCOSITY