Reactions Between Refractory Oxides and Graphite
Reactions of alumina, magnesia, spinel, and beryllia with graphite were studied in vacuum by measuring the amount of carbon monoxide formed. Two types of reactions were observed: a diffusion-controlled reaction with alumina, beryllia, and thoria, and a phase boundary-controlled reaction with magnesia, beryllia, spinel, and titania. The following activation energies were obtained: 316 kcal for Al/sub 2/O/sub 3/, 40 kcal for BeO below 1700 deg C (parabolic rate law), 61.3 kcal for BeO above 1700 deg C (linear rate law), 59.8 kcal for MgO, 59.5 kcal for spinel, and 59 kcal for TiO/sub 2/. The relative reactivities of these oxides with graphite increased in the following order: BeO, spinel, MgO, ThO/sub 2/, Al/sub 2/O/sub 3/, TiO/sub For the reactions following a linear rate law a mechanism is proposed. It was concluded that the reaction proceeds over the gas phase by dissociation of the oxide into atomic oxygen and that the desorption of carbon monoxide from the graphite surface is the rate-determining step. (auth)
- Research Organization:
- New York Univ., New York
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-17-027344
- OSTI ID:
- 4660971
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 7 Vol. 110; ISSN JESOAN; ISSN 0013-4651
- Publisher:
- The Electrochemical Society
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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