Kinetics and mechanism of thermal oxidation of sialon ceramic powders

Kenneth J D MacKenzie, Carolyn M. Sheppard, Glen C. Barris, Ann M. Mills, Shiro Shimada, Hajime Kiyono

Research output: Contribution to journalArticle

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Abstract

X-ray diffraction, solid state MAS NMR and isothermal thermogravimetry were used to study the oxidation mechanism and kinetics of pure X-phase and O′-sialon powders prepared by silicothermal synthesis. X-phase sialon (Si12Al18O39N8) begins to oxidise at above 940°C, forming amorphous silica and progressively losing nitrogen from the SiO2N2 groups to form mullite at 1200-1300°C. O′-sialon is more oxidation-resistant; although significant formation of amorphous silica occurs above 940°C, the crystalline products (silica and a small amount of mullite) appear above 1235°C. At 1400-1600°C, oxidation is progressively hindered by the formation of a protective fused silica surface layer containing octahedral Al. The oxidation kinetics can be described by a parabolic rate law, with temperature coefficients of reaction rate (Ea) of 250 and 454 kJ mol-1 for X-phase and O′-sialon, respectively. The kinetic results are discussed in the context of previous sialon powder oxidation studies.

Original languageEnglish
Pages (from-to)91-100
Number of pages10
JournalThermochimica Acta
Volume318
Issue number1-2
Publication statusPublished - 1998 Sep 7
Externally publishedYes

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Powders
ceramics
Oxidation
oxidation
Kinetics
Silicon Dioxide
silicon dioxide
kinetics
Mullite
Silica
Fused silica
thermogravimetry
Reaction rates
Thermogravimetric analysis
surface layers
reaction kinetics
Nitrogen
Nuclear magnetic resonance
Hot Temperature
Crystalline materials

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

MacKenzie, K. J. D., Sheppard, C. M., Barris, G. C., Mills, A. M., Shimada, S., & Kiyono, H. (1998). Kinetics and mechanism of thermal oxidation of sialon ceramic powders. Thermochimica Acta, 318(1-2), 91-100.

Kinetics and mechanism of thermal oxidation of sialon ceramic powders. / MacKenzie, Kenneth J D; Sheppard, Carolyn M.; Barris, Glen C.; Mills, Ann M.; Shimada, Shiro; Kiyono, Hajime.

In: Thermochimica Acta, Vol. 318, No. 1-2, 07.09.1998, p. 91-100.

Research output: Contribution to journalArticle

MacKenzie, KJD, Sheppard, CM, Barris, GC, Mills, AM, Shimada, S & Kiyono, H 1998, 'Kinetics and mechanism of thermal oxidation of sialon ceramic powders', Thermochimica Acta, vol. 318, no. 1-2, pp. 91-100.
MacKenzie KJD, Sheppard CM, Barris GC, Mills AM, Shimada S, Kiyono H. Kinetics and mechanism of thermal oxidation of sialon ceramic powders. Thermochimica Acta. 1998 Sep 7;318(1-2):91-100.
MacKenzie, Kenneth J D ; Sheppard, Carolyn M. ; Barris, Glen C. ; Mills, Ann M. ; Shimada, Shiro ; Kiyono, Hajime. / Kinetics and mechanism of thermal oxidation of sialon ceramic powders. In: Thermochimica Acta. 1998 ; Vol. 318, No. 1-2. pp. 91-100.
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