Investigation of Third Body Processes by In Vivo Raman Tribometry (Preprint)
NAVAL RESEARCH LAB WASHINGTON DC SURFACE CHEMISTRY BRANCH
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A Raman tribometer has been used to study third body processes and friction during sliding against two low friction coatings annealed boron carbide and Mo-S-Pb, a MoS2-based coating. Reciprocating sliding tests were performed in either dry or humid air with transparent hemispheres glass or sapphire loaded against the coatings. Videos and Raman spectra of the sliding contact were recorded during the tests. For annealed boron carbide, friction was controlled by a mix of H3BO3 and carbon for amorphous Mo-S-Pb, friction was controlled by MoS2 generated by sliding. Friction changes in the former were correlated to the relative amount of the two materials in the latter, the rise in friction was ascribed to a change in interfacial shear strength of MoS2, inferred from the deformation of transferred debris particles. For both coatings, interfacial sliding was the dominant mode of velocity accommodation in the sliding interface.
- Physical Chemistry