Mechanism of metal doping effect on lubricity of DLC films

On the diversity of accommodation mechanisms in the tribology of Bulk Metallic Glasses

“…The tribochemical phenomena occurring inside the contact during friction tests of both Ni and Cu materials can be compared to the tribochemical competitions observed in several studies and in which, depending on the balance of reactive molecules coming from the environments and the base element of the materials, multiphasic materials are created [44][45][46] . For example, in Ti-doped DLC lubricated by PAO oil with ZnDTP and MoDTC additives 45 , the reduction of the friction coefficient appears to result from beneficial competitive adsorption of ZnDTP and MoDTC on the surfaces. In that case, a selective tribochemical process occurred and led to the creation of Ti-rich and Zn-rich regions.…”

Tribochemical Competition within a MoS2/Ti Dry Lubricated Macroscale Contact in Ultrahigh Vacuum: A Time-of-Flight Secondary Ion Mass Spectrometry Investigation

“…Looking at a larger spatial scale and other environments, such tribochemical processes are not unique to our study here and to Numata's, 44 and they can be identified as well in the literature. For example, in Ti-doped diamond-like carbon (DLC) under wet lubrication by PAO oil with ZnDTP and MoDTC additives, 35 the reduction of the friction coefficient appears to be the consequence of improved and competitive adsorption of ZnDTP and MoDTC on the surfaces. Selective tribochemical reactions resulted in Ti-rich regions and Zn-rich regions.…”

“…Time-of-flight secondary ion mass spectrometry (ToF-SIMS) has shown great capabilities for studying tribochemical reactions within wet − and dry lubricated contacts, ,,,,− although having some limitation in terms of the quantitative nature of the measure on rough microscale samples . The use of ToF-SIMS appears sparse in tribology of dry contacts but few studies agreed and showed that superlow and ultralow friction can be achieved by a diversity of tribochemical reactions. ,,− Heavily used for carbon-based materials in dry lubricated contacts under friction in various gaseous environments, ,,,− only a few studies are looking at the tribochemical processes occurring inside the contact without an external supply of reactive gas ( g Q se = 0). , Only ToF-SIMS analysis was able to provide us with the clear evidence of such interconnectivity between solid and gaseous materials during friction tests under UHV for a crystalline c-MoS 2 -lubricated contact . Coupled with the multiple measures and observations, it allowed determining a set of chemical reactions tribologically triggered inside the contact.…”