Energetics of Si{sub x}O{sub y}C{sub z} polymer-derived ceramics prepared under varying conditions.

Journal Article · Mon Sep 01 04:00:00 EDT 2008 · J. Am. Ceram. Soc.

DOI:https://doi.org/10.1111/j.1551-2916.2008.02543.x· OSTI ID:1007403

Morcos, R M; Navrotsky, A; Varga, T; Blum, Y; Ahn, D; Poli, F; Muller, K; Raj, R ^[1]

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1. Materials Science Division

Incorporation of carbon at the molecular level can create unusual amorphous and nanostructures of Si-C-O polymer-derived ceramics by controlled pyrolysis of crosslinked polysiloxanes. These ceramics can resist crystallization to ultrahigh temperatures. In this work, we support earlier studies that the resistance to crystallization of these nanodomain networks is due to thermodynamic as well as kinetic factors. Calorimetric measurements of heats of dissolution in a molten oxide solvent show that these ceramics posses a negative enthalpy relative to their crystalline constituents (silicon carbide, cristobalite, and graphite). Si-C-O ceramics pyrolyzed at 1000 and 1450 C appear somewhat more energetically stable than those prepared at 1200 C.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC; NSF; Deutsche Forschungsgemeinschaft
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1007403
• Report Number(s): ANL/MSD/JA-68871
• Journal Information: J. Am. Ceram. Soc., Journal Name: J. Am. Ceram. Soc. Journal Issue: 9 ; Sep. 2008 Vol. 19; ISSN 0002-7820
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
CARBON
CERAMICS
CRISTOBALITE
CRYSTALLIZATION
DISSOLUTION
ENTHALPY
GRAPHITE
KINETICS
NANOSTRUCTURES
OXIDES
PYROLYSIS
SILICON
SOLVENTS
TEMPERATURE RANGE OVER 4000 K
THERMODYNAMICS