Abstract
Nanocrystalline manganese oxide powders were synthesized by an inert gas condensation technique. The manganese oxide powders, prepared from vaporized metallic manganese in a helium pressure of 10 mbar, then oxidized under the oxygen pressures of 50 and 100 mbar, exhibited a mixture of β-Mn, MnO and Mn3O4 phases. X-ray diffractometry (XRD) analysis identified the predominant oxide formation of the as-prepared powder to be the phase of MnO. In situ synchrotron XRD and differential scanning calorimetry (DSC) data showed that synthesized manganese powder converts from β-Mn to MnO in the temperature range of 150-250 °C and subsequently converts to Mn3O4 above 250 °C. Transmission electron microscopy examinations confirmed that oxidation starts from the surface of the condensed β-Mn particles. Detailed valance variations of manganese of the resulting powders were investigated by synchrotron X-ray absorption spectroscopy techniques.
Original language | English |
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Pages (from-to) | 1661-1666 |
Number of pages | 6 |
Journal | Ceramics International |
Volume | 34 |
Issue number | 7 |
DOIs | |
Publication status | Published - Sept 2008 |
Externally published | Yes |
Keywords
- B. X-ray methods
- C. Thermal properties
- Gas phase reaction
- In situ synchrotron X-ray diffractometry
- Manganese oxide
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Process Chemistry and Technology
- Surfaces, Coatings and Films
- Materials Chemistry