Abstract
To clarify the oxidation mechanism □□2□ to CuO, □□2□ oxidation was studied at 600-1050°C under1 atm □2. The □□2□ specimens were prepared through completely oxidizing 99.99999 and 99.5% pure copper at 1000°C in an Ar +1% □2 atmosphere. The oxidation kinetics □□ 2□ specimens prepared from both purity levels followed the logarithmic law, not the parabolic law or the cubic law as reported in the literature. The activation energy for □□2□ oxidation is relatively high in the lower-temperature range, but becomes very small or even negative at higher temperatures. The logarithmic oxidation rate law can be explained by Davies et al.'s model related to grain-boundary diffusion in the oxide layers. The very small or negative activation energies in the higher-temperature range can be attributed to the very small thermodynamic driving force and the fast lateral growth of CuO grains related to a sintering effect. The influence of small amount of impurities is also discussed.
Original language | English |
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Pages (from-to) | 207-222 |
Number of pages | 16 |
Journal | Oxidation of Metals |
Volume | 62 |
Issue number | 3-4 |
DOIs | |
Publication status | Published - 2004 Oct 1 |
Keywords
- Activation energies
- CuO
- CuO
- Grain-boundary diffusion
- Oxidation
- Oxidation rate law
ASJC Scopus subject areas
- Metals and Alloys