Abstract
Molybdenum disulfide (MoS 2) and molybdenum trioxide are investigated using Raman spectroscopy with emphasis on the application to tribological systems. The Raman vibrational modes were investigated for excitation wavelengths at 632.8 and 488 nm using both micro-crystalline MoS 2 powder and natural MoS 2 crystals. Differences are noted in the Raman spectra for these two different wavelengths, which are attributed to resonance effects due to overlap of the 632.8 nm source with electronic absorption bands. In addition, significant laser intensity effects are found that result in laser-induced transformation of MoS 2 to MoO 3. Finally, the transformation to molybdenum trioxide is explored as a function of temperature and atmosphere, revealing an apparent transformation at 375 K in the presence of oxygen. Overall, Raman spectroscopy is an useful tool for tribological study of MoS 2 coatings, including the role of molybdenum trioxide transformations, although careful attention must be given to the laser excitation parameters (both wavelength and intensity) when interpreting Raman spectra.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 301-310 |
| Number of pages | 10 |
| Journal | Tribology Letters |
| Volume | 42 |
| Issue number | 3 |
| DOIs | |
| State | Published - Jun 2011 |
| Externally published | Yes |
Keywords
- Molybdenum disulfide
- Oxidation resistance
- Raman spectroscopy
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering
- Surfaces and Interfaces
- Surfaces, Coatings and Films