Kinetics of thermal oxidation of silicon nitride powders
- Los Alamos National Lab., NM (United States). Materials Science and Technology Div.
The kinetics of thermal oxidation of H.C. Starck M-11 and Ube SN-E10 Si{sub 3}N{sub 4} powders was evaluated in the temperature range 650--1,200 C using isothermal and nonisothermal thermogravimetric analysis, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. Between 700 and 1,200 C, the isothermal kinetics was modeled equally well using the Ginstling-Brounshtein and Zuravlev-Lesokhin-Tempel`man equations. Despite their similar particle sizes and surface areas, the two powders exhibited different oxidation kinetics. The activation energies for oxidation of the M-11 and SN-E10 powders were determined to be 400 and 540 kJ/mol, respectively, between 1,000 and 1,200 C, and 230 and 260 kJ/mol, respectively, between 700 and 1,000 C. the parabolic rate constants for oxidation of the two powders were comparable to those reported in the literature for monolithic, chemically-vapor-deposited Si{sub 3}N{sub 4} at the higher temperatures. At lower temperatures, the oxidation kinetics of the M-11 powder was nearly linear, whereas the kinetics of the SN-E10 powder remained power-law dependent.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 417763
- Journal Information:
- Journal of the American Ceramic Society, Vol. 79, Issue 11; Other Information: PBD: Nov 1996
- Country of Publication:
- United States
- Language:
- English
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