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Newtonian Viscosity of Amorphous Silicon Carbonitride at High Temperature

An, Linan ; Riedel, Ralf ; Konetschny, Christoph ; Kleebe, Hans-Joachim ; Raj, Rishi :
Newtonian Viscosity of Amorphous Silicon Carbonitride at High Temperature.
[Online-Edition: http://dx.doi.org/10.1111/j.1151-2916.1998.tb02489.x]
In: Journal of the American Ceramic Society, 81 (5) pp. 1349-1352. ISSN 00027820
[Artikel], (1998)

Offizielle URL: http://dx.doi.org/10.1111/j.1151-2916.1998.tb02489.x

Kurzbeschreibung (Abstract)

The creep viscosity of chemical-precursor-derived silicon carbonitride (SiCN), which is known to remain predominantly amorphous at temperatures below 1400°C, was measured in the temperature range 1090-1280°C. Experiments were done in uniaxial compression at constant loads in pure nitrogen atmosphere. The creep behavior exhibited three stages. In stage I the strain rate decreased rapidly with time and deformation was accompanied by densification. In stage II the samples exhibited a steady-state creep rate. In stage III, which commenced after long-term deformation, creep gradually declined to rates that were below the sensitivity of our apparatus. The relative density of the specimens during stage II and stage III remained constant at ≅2.3 g/cm3. The shear viscosity in stage II was nearly Newtonian and was measured to be 1.3 × 1013-5.0 1013 Pa·s at 1280°C, which is approximately 103 times the value for fused silica. The creep-hardened as well as uncrept specimens contained silicon nitride crystallites. The volume fraction of these crystals was variable but always less than 5%. Such a small volume fraction of crystals does not explain the dramatic creep-hardening behavior in stage III, even if it is assumed that the crystals formed during creep deformation in stage II.

Typ des Eintrags: Artikel
Erschienen: 1998
Autor(en): An, Linan ; Riedel, Ralf ; Konetschny, Christoph ; Kleebe, Hans-Joachim ; Raj, Rishi
Titel: Newtonian Viscosity of Amorphous Silicon Carbonitride at High Temperature
Sprache: Englisch
Kurzbeschreibung (Abstract):

The creep viscosity of chemical-precursor-derived silicon carbonitride (SiCN), which is known to remain predominantly amorphous at temperatures below 1400°C, was measured in the temperature range 1090-1280°C. Experiments were done in uniaxial compression at constant loads in pure nitrogen atmosphere. The creep behavior exhibited three stages. In stage I the strain rate decreased rapidly with time and deformation was accompanied by densification. In stage II the samples exhibited a steady-state creep rate. In stage III, which commenced after long-term deformation, creep gradually declined to rates that were below the sensitivity of our apparatus. The relative density of the specimens during stage II and stage III remained constant at ≅2.3 g/cm3. The shear viscosity in stage II was nearly Newtonian and was measured to be 1.3 × 1013-5.0 1013 Pa·s at 1280°C, which is approximately 103 times the value for fused silica. The creep-hardened as well as uncrept specimens contained silicon nitride crystallites. The volume fraction of these crystals was variable but always less than 5%. Such a small volume fraction of crystals does not explain the dramatic creep-hardening behavior in stage III, even if it is assumed that the crystals formed during creep deformation in stage II.

Titel der Zeitschrift, Zeitung oder Schriftenreihe: Journal of the American Ceramic Society
Band: 81
(Heft-)Nummer: 5
Fachbereich(e)/-gebiet(e): Fachbereich Material- und Geowissenschaften
Fachbereich Material- und Geowissenschaften > Geowissenschaften > Geomaterialwissenschaften
Fachbereich Material- und Geowissenschaften > Materialwissenschaften
Fachbereich Material- und Geowissenschaften > Materialwissenschaften > Disperse Feststoffe, Dispersive Solids
Fachbereich Material- und Geowissenschaften > Geowissenschaften
Hinterlegungsdatum: 15 Nov 2012 09:14
Offizielle URL: http://dx.doi.org/10.1111/j.1151-2916.1998.tb02489.x
ID-Nummer: 10.1111/j.1151-2916.1998.tb02489.x
Sponsoren: Supported by the North Atlantic Treaty Organization, and partially by a grant from the Division of Materials Research at the National Science Foundation (DMR-9796100).
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