Imperial College London
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ProfessorHughSpikes

Faculty of Engineering, Department of Mechanical Engineering

Professor
 
 
 
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Contact

 

+44 (0)20 7594 7063h.spikes

 
 
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Assistant

 

Mrs Chrissy Stevens +44 (0)20 7594 7064

 
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Location

 

673City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Garcia:2021:10.1038/s41598-021-81326-0,
author = {Garcia, Gonzalez C and Ueda, M and Spikes, H and Wong, J},
doi = {10.1038/s41598-021-81326-0},
journal = {Scientific Reports},
pages = {3621--3621},
title = {Temperature dependence of Molybdenum dialkyl dithiocarbamate (MoDTC) tribofilms via time-resolved Raman spectroscopy},
url = {http://dx.doi.org/10.1038/s41598-021-81326-0},
volume = {11},
year = {2021}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Molybdenum dialkyl dithiocarbamate (MoDTC) is a friction reducing additive commonly used in lubricants. MoDTC works by forming a low-friction molybdenum disulphide (MoS<sub>2</sub>) film (tribofilm) on rubbed surfaces. MoDTC-induced MoS<sub>2</sub> tribofilms have been studied extensively ex-situ; however, there is no consensus on the chemical mechanism of its formation process. By combining Raman spectroscopy with a tribometer, effects of temperature and shear stress on MoS<sub>2</sub> tribofilm formation in steel-steel contacts were examined. Time-resolved Raman spectra of the tribofilm were acquired, together with the instantaneous friction coefficient. The tribofilm is constantly being formed and removed mechanically during rubbing. Increasing shear stress promotes MoS<sub>2</sub> formation. The nature of the tribofilm is temperature-dependent, with high-temperature tribofilms giving a higher friction than lower temperature films. Below a critical temperature T<sub>c</sub>, a small amount of MoS<sub>2</sub> gives significant friction reduction. Above T<sub>c,</sub> a patchy film with more MoS<sub>2</sub>, together with a substantial amount of amorphous carbon attributed to base oil degradation, forms. The composition of this tribofilm evolves during rubbing and a temporal correlation is found between carbon signal intensity and friction. Our results highlight the mechanochemical nature of tribofilm formation process and the role of oil degradation in the effectiveness of friction modifier MoDTC.
AU  - Garcia,Gonzalez C
AU  - Ueda,M
AU  - Spikes,H
AU  - Wong,J
DO  - 10.1038/s41598-021-81326-0
EP  - 3621
PY  - 2021///
SN  - 2045-2322
SP  - 3621
TI  - Temperature dependence of Molybdenum dialkyl dithiocarbamate (MoDTC) tribofilms via time-resolved Raman spectroscopy
T2  - Scientific Reports
UR  - http://dx.doi.org/10.1038/s41598-021-81326-0
UR  - http://hdl.handle.net/10044/1/86480
VL  - 11
ER  -
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