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Volatilization and Transport Mechanisms During Cr Oxidation at 300 °C Studied In Situ by ToF-SIMS.
- Source :
- Oxidation of Metals; Oct2017, Vol. 88 Issue 3/4, p423-433, 11p
- Publication Year :
- 2017
-
Abstract
- The oxidation of chromium at 300 °C was investigated in situ by ToF -SIMS for three different oxygen pressures ( $$P_{{{\text{O}}_{2} }} = 2.0 \times 10^{ - 7}$$ , 6.0 × 10 and 2.0 × 10 mbar). Sequential exposure to the O isotopic tracer was performed to reveal the governing transport mechanism in the oxide film. The evolution of the oxide thickness was monitored. Volatilization of CrO was evidenced. A model was used to describe the kinetics resulting from the measurements. Both the parabolic and volatilization constants showed a dependence on oxygen partial pressure like $$P_{{{\text{O}}_{2} }}^{ - 1/n}$$ , with n = 1.9 ± 0.1, indicating a defect structure mainly consisting of oxygen vacancies. The re-oxidation in O shows a growth of the oxide layer at the metal/oxide interface, demonstrating an oxidation process governed by anionic transport via oxygen vacancies. The diffusion coefficient of oxygen in the oxide was determined by fitting the ToF -SIMS depth profiles. It is 2.0 × 10 cm s. [ABSTRACT FROM AUTHOR]
- Subjects :
- CHROMIUM oxide
OXIDE coating
OXYGEN
METALLIC oxides
OXIDATION
Subjects
Details
- Language :
- English
- ISSN :
- 0030770X
- Volume :
- 88
- Issue :
- 3/4
- Database :
- Complementary Index
- Journal :
- Oxidation of Metals
- Publication Type :
- Academic Journal
- Accession number :
- 125841902
- Full Text :
- https://doi.org/10.1007/s11085-017-9756-y